MOSQUITOES Where Mosquitoes Breed by Millions. MOSQUITOES 
HOW THEY LIVE; HOW THEY CARRY 
DISEASE; HOW THEY ARE CLAS- 
SIFIED; HOW THEY MAY 
BE DESTROYED 
BY 
L. O. HOWARD, PH.D. 
DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C. 
NEW YORK 
MCCLURE, PHILLIPS & CO 
1<> o l Copyright, June, 1901, by 
McCLURE, PHILLIPS & CO. INTRODUCTION 
SOME years ago I was visiting a family in the moun- 
tains. It was during a dry season, and water was 
scarce. There were no swamps, no lakes or pools, 
and the drinking-water was taken from springs ; yet mos- 
quitoes were so plentiful that it was necessary to screen 
the porches, that sitting out of an evening might be made 
possible. I asked where the water came from in which 
they washed their clothes, and they replied, as expected, 
“ From a rain-water tank,” which, as it happened, was sit- 
uated under the porch. I investigated the tank and found 
it literally alive with mosquito larvae. A pint of kero- 
sene stopped the breeding, and as the water was drawn 
from a faucet near the bottom of the tank the kerosene 
did not injure it. 
The indifference of this family as to the source of their 
local mosquito pest, or rather their combined ignorance 
of and indifference to the subject of the breeding-places, 
was at that time—and it was not so very long ago—char- 
acteristic of people in general. It was my good fortune, 
through the wide-spread newspaper accounts of my kero- 
sene experiments in the Catskill Mountains in 1892, to 
become more or less identified with many practical experi- 
ments in the destruction of mosquitoes from that time 
on. Interest in the subject became very great, especially 
V VI 
INTRODUCTION 
among summer residents of the country, and especially 
near the sea-sliore, even before the agency of mosquitoes 
in the spread of disease became established, and before 
it became a generally accepted fact. With the very per- 
fect that the mosquitoes of the genus Anopheles are 
instrumental in the carriage of malaria, the interest be- 
came intensified, and the late discovery of our Army 
Yellow-fever Commission in Cuba, that a mosquito is the 
conveyor of yellow fever, has added to the general interest 
in the subject. In fact, the whole mosquito question is a 
live tox>ic of the day. Knowledge of mosquito habits is 
more general than at any previous time, and almost every- 
one is interested in the subject of mosquito extermina- 
tion. With the knowledge which we now jiossess, it 
seems almost incredible that x>e°ple should all these 
years have suffered, more or less patiently, the torment- 
ing bites of Culex and the insidious but more dangerous 
Xnmctures of Anoxdieles without making the slightest ef- 
fort to abate the nuisance and the danger, beyond slap- 
ping, in a revengeful way, at individual biters. In many 
places infested with mosquitoes nothing could be easier 
than to put a stox> to the whole tormenting plague. In 
many other cases the problem is a more difficult one, but 
in even the worst cases, by a judicious effort, which 
should be a community effort, and by the expenditure of 
a greater or smaller amount of money, much relief can be 
gained. In fact, Mr. W. J. Matlieson, of New York, was 
quite right when, in the summer of 1900, just before com- 
mencing a successful crusade against the mosquitoes on 
the north shore of Long Island, he wrote me that there INTROI) NOTION 
VII 
seemed to him to be no more reason for enduring the 
mosquito scourge than in allowing small-pox to ravage 
communities, as it used to do before the days of Jenner. 
Work against mosquitoes is being undertaken everywhere, 
by individuals and by communities. The interest in the 
subject, from both medical and hay points of view, has be- 
come so great that persons are not satisfied with half 
knowledge, but must know the whole mosquito story, and 
it has been with the purpose of supplying in some part 
this demand for information, that this book has been pre- 
pared. It tells what is known about mosquitoes from the 
biological point of view, from the medical point of view, 
and from the practical side. An especial effort has been 
made to show, in a straightforward way, to physicians how 
the different kinds of mosquitoes can be distinguished, 
and to indicate the characteristic habits and breeding- 
places of those forms which spread malaria and yellow 
fever. Directions are given for collecting mosquitoes and 
for rearing their early stages, and an especial effort has 
been made to display fully and practically the remedial 
measures which should be adopted in mosquito-ridden 
neighborhoods. TABLE OF CONTENTS 
PAGE 
Introduction, v 
CHAPTER I. 
Mosquitoes in General, 1 
The Life Round of Mosquitoes, ..... 1 
Parthenogenesis Among Mosquitoes, ... 4 
How Long can the Larvae Live Under Water? . . 5 
How Long may the Larvae Live ? .... 6 
How Long can the Larvae Live Out of Water? . . 7 
Length of Life of Adult Mosquitoes, .... 9 
Transformations of Mosquitoes Artificially Hastened, 12 
Mosquito Songs, .13 
How Far do Mosquitoes Fly ? Are They Carried by 
Winds? 16 
Carriage of Mosquitoes by Railway Trains and other Con- 
veyances, ......... 25 
Queer Places in which Mosquitoes Breed, . . .28 
Food of Adult Mosquitoes, ...... 34 
Abundance of Mosquitoes, ...... 39 
The Northern Mosquitoes, ..... .42 
The Poison of Mosquito Bites, ..... .44 
Malaria and Mosquitoes, 48 
CHAPTER II. 
IX TABLE OF CONTENTS 
X 
CHAPTER III. 
PACE 
The Common Mosquitoes of the Genus Culex, . . 00 
Dr. J. B. Smith’s Observations on Culex pungens, . . 83 
CHAPTER IV. 
The Malarial Mosquitoes of the Genus Anopheles, . 91 
The Life History of Anopheles maculipenjiis, . . 93 
European Observations on the Same Species, . . . 107 
Natural Breeding Places of Anopheles, .... 109 
The North American Species of Anopheles, . . .113 
Food of Anopheles Larvae, . . . . . .117 
Length of Life of Adult Anopheles, ..... 118 
How Anopheles Bites, .119 
CHAPTER V. 
Mosquitoes and Yellow Fever ; Mosquitoes and Fili- 
ARIASIS, 121 
The Yellow-fever Mosquito, 131 
Mosquitoes and Filariasis, . . . . . .140 
CHAPTER VI. 
Other Genera of North American Mosquitoes, . . 144 
Genus Psorophora Desvoidy, ...... 144 
Genus Megarliinus Desvoidy, ...... 152 
Genus A Odes Meigen, . . . . . . .153 
Stegomyia, Toxorhynchites, TJranotaeniaand Conchylias- 
tes, 155 
CHAPTER VII. 
Natural Enemies of Mosquitoes, . . . . .156 TABLE OF CONTENTS 
XI 
CHAPTER VIII. 
PAGE 
Remedies Against Mosquitoes, 167 
Remedial Work Against the Early Stages, . . .170 
The Use of Kerosene on Breeding Pools, . . .171 
Other Substances Against the Early Stages of Mos- 
quitoes, 193 
The Abolition of Breeding Places by Drainage or by 
Filling, 198 
Introduction of Fish into Fishing Ponds, . . .211 
Remedies Against Adult Mosquitoes, . . . .211 
Eucalyptus, ........ 215 
The Castor-oil Plant, . . . . . .217 
Remedies for the Bites, . . . . . . .218 
CHAPTER IX. 
How to Collect and Preserve Mosquitoes, . . . 220 
CHAPTER X. 
The Classification of the United States Mosquitoes, 229 LIST OF ILLUSTRATIONS 
Where Mosquitoes Breed by Millions, . . . Frontispiece 
FIG. PAGE 
1. Culex tceniorhynchus, Common Atlantic Coast “ring- 
legged ’ ’ Mosquito, . ... ... 8 
2. Section of Mosquito’s Head showing poison gland, . . 45 
3. Salivary Glands of Culex and Anopheles (after Christo- 
phers) .... 46 
4. Experimental House Occupied by J)rs. Sam bon and Low 
on the Campagna in the Summer of I960 (from the 
Journal of Tropical Medicine), . .... 53 
5. Malaria House on the Campagna, seen from a distance 
(from the Journal of Tropical Medicine), . . .55 
6. Egg Mass of Culex pungens, 67 
7. Young Larvae of Culex pungens, 69 
8. Mouth-parts of Larva of Culex pungens, . . . .70 
9. Full-grown Larva of Culex pungens, . . . .71 
10. Pupa of Culex pungens, with Anal Segment below, 
greatly enlarged, ........ 72 
11. Adult Male of Culex pungens, 74 
12. Adult Female of Culex pungens, 75 
13. Resting Position of Anopheles maculipennis, . . .95 
14. Anopheles and Culex (after Waterhouse), . . .95 
15. Anopheles maculipennis, Adult, 96 
16. Egg Mass of Anopheles maculipennis, . . . .97 
XIII XIV 
LIST OF ILLUSTRATIONS 
FIG. • PAGE 
17. Individual Eggs of Anopheles maculipennis, . . .98 
18. Young Larva of Anopheles maculipennis, . . . 100 
19. 19a. Half-grown Larva of Anopheles maculipennis in 
comparison with Culex Larva, . . . . .101 
20. Half-grown Larva of Anopheles maculipennis, . . 102 
21. Full-grown Larva of Anopheles maculipennis, showing 
head upside down, with top of head above, at left; 
greatly enlarged, 103 
22. Enlarged Head of Larva of Anopheles maculipennis, un- 
der side (after Nuttall), . . . . . . .104 
23. Enlarged Head of Larva of Anopheles maculipennis, from 
side (after Nuttall), . . . . . . .105 
24. Pupa of Anopheles in comparison with Pupa of Culex, . 100 
25. Head of Full-grown Larva of Anopheles punctipennis, . 108 
26. Anopheles punctipennis, adult female, . . . .110 
27. Anopheles 'punctipennis, adult male, from side, . .111 
28. Anopheles crucians, adult female, . . . . .114 
29. Anopheles argyritarsis, adult female, . . . .110 
30. Stegomyia fasciata, adult female, 123 
31. Stegomyia fasciata, adult male, 127 
32. Stegomyia fasciata, adult male, from side, . . . 132 
33. Stegomyia fasciata, body scales, 133 
34. Larva and Pupa of Stegomyia fasciata, with enlarged 
parts, .......... 135 
35. Mouth-parts of Larva of Stegomyia fasciata, . . .137 
30. Cross Section of Head and Beak of Mosquito, showing 
Filiarias entering Beak, ...... 141 
37. Psorophora ciliata, adult female, ..... 145 
38. Females of Psorophora ciliata at rest on side wall and 
ceiling, 146 
39. Male of Psorophora ciliata, from side, . . . .147 
40. Young Larva of Psorophora ciliata, ..... 148 LIST OF ILLUSTRATIONS 
XV 
PIG. PAGE 
41. Full-grown Larva and Pupa of Psorophora ciliata, with 
enlarged parts, ........ 149 
42. Aedes fuscus, adult female, 153 
43. Toxorhy whites rutilus, adult female, . . . .154 
44. Gasterosteus aculeatus—Stickleback, . . . .158 
45. Gambusia affinis, male and female—Top-minnows, . 159 
46. Fundulus notatus— Top-minnow 160 
47. Lepomis pallidus—Sunfish, . . . . . .163 
48. Claws of Front Feet of Culex stimulans, male and fe- 
male, .......... 230 
49. Claws of Front Feet of Culex perturbans, male and fe- 
male, .......... 231 
50. Wing of Culex consobrinus and Culex pipiens, showing 
petiole of first submarginal cell, ..... 232 MOSQUITOES I 
Mosquitoes in General 
The Life Round of Mosquitoes. 
ALL mosquitoes, so far as known, are aquatic in 
their early stages. It has never been shown that 
any of them lay their eggs anywhere except in 
water. Their larvae live under the surface of the water, 
although they are true air-breathers; that is to say, they 
must come to the surface of the water to breathe. This 
breathing is performed through branched tracheal tubes 
within the body, which terminate in an orifice at the end 
of a prolongation of one of the last segments of the ab- 
domen, and which from this fact is known as the respira- 
tory tube. This tube is pushed at intervals up through 
the surface film of the water and air is drawn down into 
the tracheae. The larvae feed either at the surface or 
below the surface, and their food is composed of all sorts 
of floating particles, and in the case of some of the larger 
forms they may even bite aquatic vegetation. They are 
rapid breeders and pass the pupal condition also in the 
water, but floating normally at the surface. In the pupae 
they breathe not from a breathing tube at the anal end of 
the abdomen, but from two trumpet-shaped tubes issuing 
1 2 
MOSQUITOES 
from the top of the thorax. The thorax of all is much 
swollen, and with all pupae the bodies seem lighter than 
air, so that they float at the surface without exertion. The 
pupae, however, are active—sometimes very active. The 
abdomen, with anal oar-like Haps, may be quickly and 
violently agitated so as to draw them down below the 
surface, when it becomes necessary to escape from a fish 
or from some predatory aquatic insect. This great activity 
is necessary for the preservation of species, since stagnant 
pools abound with carnivorous forms of life, and such a 
little, fat morsel as a mosquito pupa, if it always stayed 
quietly at the surface, would stand no chance. When 
one tries to catch a pupa with his thumb and forefinger, 
at even the approach of the hand it disappears like a 
flash, rising slowly to the surface again when the active 
movements of the abdomen cease; that is to say, when 
it gets tired or when danger ceases to threaten. 
All mosquitoes, so far as known, are rather rapid 
breeders. They pass through several generations in the 
course of a year, and hibernate in both adult and larval 
stages. Over-wintering mosquitoes may frequently be 
found in the cellars of houses, in cold garrets, in barns, 
under the lids of water-tanks, under bridges and stone 
culverts. In the extreme Southern States many mosqui- 
toes are active all through the winter, and in most tropi- 
cal regions they may breed all the year round. In dry, 
tropical regions, however, they breed only through the 
rainy season, and in the dry spell the species is perpetu- 
ated by the persistence of the adults, which either remain 
active, or more usually rather inactive or dormant, just Fig. 1.—Common Atlantic Coast “wing-legged” Mosquito (Cu/ex 
sollicitans) ; greatly enlarged. (Author’s illustration.) 4 
MOSQUITOES 
as though they were hibernating. In such dry spells 
the males generally die and the gravid females live over. 
This is also the case in winter hibernation in the north ; 
females are, as a rule, impregnated when hibernation time 
comes, and they live until the ice melts and the weather 
becomes of the proper temperature for the laying of eggs. 
As shown by recent observations by Mr. J. Turner Brake- 
ley and Dr. John B. Smith, larvae, on the approach of 
winter, may be frozen up in the ice and when thawed out 
resume their growth, so that many undoubtedly hibernate 
in this way. 
Parthenogenesis Among Mosquitoes. 
We have just stated that the males impregnate the 
females and then die during the early winter or during 
the early part of the dry spell in tropical countries, but 
there is evidence that parthenogenesis, or virgin birth, 
sometimes occurs with mosquitoes, as it does with so 
many of the lower forms of life. 
Professor Y. L. Kellogg, of Stanford University, reared 
in a covered jar, from the pupa a female mosquito which 
almost immediately laid eggs. There was no other mos- 
quito in the jar and certainly no mating. From these 
eggs there hatched larvae, which grew very slowly and 
nearly reached full growth before they died. None of 
them succeeded in reaching the pupa stage. It is possi- 
ble that they died on account of their abnormal birth, but 
there is also the possibility that they died from lack of 
proper food, and that under other conditions adults MOSQUITOES IN GENERAL 
5 
might have been reared. Professor Kellogg’s observa- 
tion indicates plainly that interesting studies can be 
made with mosquitoes in this direction, and it will be 
especially interesting to observe the sex of the adults 
reared from wigglers of virgin birth. 
How Long can the Larvae Live Under Water? 
In observations which I have made upon mosquito 
larvae of the genus Culex, I have been unable to time 
them below the surface for more than two minutes. As a 
rule they return to the surface to breathe after the expi- 
ration of not more than a minute. With the larvae of 
Anopheles, as will be shown later, the case is different. 
Although the larvae remain at the surface of the water 
during the early part of their lives, when they become 
full grown they will descend to the bottom and mouth 
over the slimy grains of sand or water-plants which are to 
be found there. In this operation they have been timed 
by one of my assistants, Miss Sullivan, and remained 
ten minutes before ascending for air. It seems also, 
from observations made by Dr. John B. Smith, that even 
Culex larvae may stay below for a longer period than I 
have observed. In the Entomological News for March, 
1901, he states that he has timed them under water for as 
long a period as ten minutes, and in a later publication 
states that these same larvae which were Culex pungens 
which had been taken in ice, remained under water for 
fifteen minutes and more. 6 
MOSQUITOES 
How Long may the Larvre Live? 
Professor Kellogg reported an interesting series of ob- 
servations in the Entomological News for April, 1899, in 
which he shows that eggs were laid by a mosquito in his 
laboratory August 9tli. (The eggs, by the way, were laid at 
4.30 in the afternoon, a novel fact in itself, since it has 
been supposed that they were only laid after dark, and 
presumably usually in the dark hours of early morning.) 
These eggs hatched October 10th, and were kept alive in a 
jar of Avater at a temperature of from 50° to 75° P. under 
normal conditions as regards light. They grew in size 
very sloAvly and one after another died. But the sole 
survivor lived until February 16th, when it died at the 
ripe old age of four months and a Aveek. None of them 
reached the pupal condition. As mentioned above, Pro- 
fessor Kellogg thinks that their death may haAre been 
due to the fact that their mother Avas a virgin and the 
sloAvness of their groAvtli may have been due to lack of 
proper food and water. 
We have stated above that mosquitoes hibernate in the 
adult condition. That has been a matter of common obser- 
vation and has been a generally accepted fact. I have 
always supposed it to be the only mode of hibernation, 
but an observation by Mr. J. Turner Brakeley, of Hor- 
nerstown, N. J., made during the past winter, indicates 
that they may occasionally pass the winter in the larval 
condition. Dr. John B. Smith wrote me, under date of 
January 30, 1901, that Mr. Brakeley went out into the MOSQUITOES IN GENERAL 
7 
marshes and collected a considerable number of the 
leaves of the pitcher plant (Sarracenia) filled with a solid 
mass of ice. He brought them into the house and 
thawed out the contents, and as a result sent Hr. Smith 
two bottles of very lively mosquito larvae. It seems that 
the temperature of the marshes had been 2|° F. below zero 
and everything had been frozen solid for some time. 
Mr. Brakeley wrote that the larvae were embedded in dif- 
ferent parts of the ice, and that in looking through the ice 
you could see the insects. He sent over one hundred of 
these thawed-out larvae to Dr. Smith, who stated that 
they reached him in good condition and that they lived, 
moulted, and grew thereafter in his laboratory. Adults 
issued in March and proved to be Culex pungens. The 
great numbers in which these larvae were found, suggests 
to Dr. Smith that larval hibernation must be extremely 
common, not only in New Jersey and in pitcher plants, 
but elsewhere and in other accumulations of water. The 
observations are of extreme interest and importance. 
How Long can the Larvae Live Out of Water? 
The fact that these insects remained dormant when 
frozen lip in ice for an indefinite period, from the obser- 
vations of Mr. Brakeley, might at first seem to indicate 
that the theory which lias been advanced, that when their 
mud bottomed breeding-places dry up they remain alive 
in the earth, is in a measure substantiated. But, in 
reality, it has little bearing upon summer temperature 
conditions. Experiments which I have tried on a small 8 
MOSQUITOES 
scale in glass vessels have shown that the larvae of Culex 
will exist for some little time in wet mud and that some 
of them will successfully transform after water has been 
added, but in no case were we able to revive larvae in 
mud from which the water had been drawn off for more 
than forty-eight hours, and after twenty-four hours only 
a small proportion of the larvae revived. These results 
accord very accurately with those reached by English 
observers in Africa, and, in fact, accurate observations 
have not carried the larvae out of water alive for more 
than forty-eight hours. The impression to the contrary 
has probably been gained from observations on pools 
which in reality did not entirely dry up. Mr. C. A. 
Sperry, of Chicago, has made observations upon a pond 
which dried up and in which he could find no dead larvae, 
but he writes that after a week it rained and as soon as 
the rain stopped he found the mosquito larvae all through 
the water as lively as ever, and they began to issue as 
adults in about a week from that time. Mr. Benjamin S. 
Pascal, of Newfield, N. »T., has sent to me an account of 
observations of his own which indicate to him that mos- 
quitoes may breed in grass or moist earth. 
In tlie summer of 1900, I watched a slowly evaporating- 
pool with great interest. It contained a surface area of 
about twenty-four square feet, and was fed entirely by 
rain-water and surface drainage. It was well stocked 
with mosquito larvae, and after a long drought the water 
was observed to have evaporated almost entirely, only a 
small puddle remaining in the centre, which contained at 
the outside only three or four cubic inches of water. It MOSQUITOES IN GENERAL 
9 
was dark in color, owing to the drainage from a manure- 
pile near by, and when glanced at casually showed no 
signs of life ; but on dipping in a coffee-strainer it was 
found to be literally massed with nearly full grown mos- 
quito larvae, many hundreds of which had been brought 
together into this restricted place. Drying continued 
until there was almost no water left, but before the larvae 
died, that is to say, about twenty-four hours after the 
water contents were estimated at from three to four cubic 
inches, there came a heavy rainstorm which filled the 
pond with water, after which it was seen to contain ap- 
parently its usual stock of mosquito larvae. From this 
observation we are able to estimate the usual happenings 
in a mosquito pool. As the water dries the larvae grad- 
ually retire to the deepest point, and after the pool is 
apparently dried up there is still enough moisture at 
this deepest point to keep the larvae alive a number of 
hours. That they may die, and that, as I believe, they 
invariably do die in the absence of all moisture and in a 
space of time which must be reckoned by hours and not 
by days, is evidenced by the laboratory observations 
mentioned above. 
Length of Life of Adult Mosquitoes. 
It is very difficult, in fact practically impossible, to 
estimate the normal length of life of the adult of any 
species of insect that flies. We may keep them in con- 
finement and count the few days of their life, but the 
conditions are abnormal and cannot be made perfectly 10 
MOSQUITOES 
normal. An insect in a breeding-cage may die in twenty- 
four hours, but that does not mean that it may not live 
for weeks outside. Certain insects die quickly from 
fright under such conditions, or from violent efforts to 
escape. I once covered a very large Yucca plant with 
gauze netting and placed under the netting about a hun- 
dred honey bees, in order to see whether the flowers of 
Yucca could be fertilized by bees. In twenty-four hours 
every one of the insects was dead, and yet we know that 
the honey bee is a long-lived insect. Such evidence as 
we have, however, shows that mosquitoes are also long- 
lived. It seems that they cannot live many days with- 
out plenty of air. Dr. Yeazie, of New Orleans, writes 
me that he has kept them alive with various substances 
for a month. Without water or food, the limit seemed 
to him, from his observations, to be five days for all va- 
rieties lie tried. If there is no water in the house he 
states that the mosquitoes will leave the house and seek 
water. He has seen them repeatedly go down into a 
pitcher or a glass, remain for a few minutes, and then fly 
away. He thinks that they do that principally to get a 
drink, although he has found eggs in a glass of water 
and in pitchers. Mr. Mitchell, of Victoria, Tex., how- 
ever, writes that he kept a number of mosquitoes in a 
box once, to see how long they could live on air, and that 
on the twenty-first day none had died. Medical ob- 
servers in their experimental work with the mosquitoes 
of the genus Anopheles have been able to keep adults 
alive under glass, by feeding them upon slices of banana 
or some other fruit, for weeks, the banana being renewed MOSQUITOES IN GENERAL 
11 
every three or four days. Dr. Woldert, of Philadelphia, 
has kept adults for two weeks or more in a bottle with a 
slice of banana, sprinkling the gauze-covering occasion- 
ally with water. He has even kept them for from fifty 
to sixty days, but this was in the fall of the year, and, as 
we have elsewhere shown, mosquitoes hibernate in the 
adult condition and the significant life-period of the 
adult is the summer period. We know that they will 
live through the winter, but we do not know whether, 
under normal conditions, those hatching in the spring 
will live through even half the summer. There used to 
be a current idea that when a female mosquito sucks a 
full meal of blood she is never able to bite again, since 
it was thought that she is unable to thoroughly digest 
such a meal. This idea, however, has been completely 
exploded in the experimental medical work, and a more 
approximate estimate of the length of the adult life has 
been reached in this experimental medical work, than 
has been elsewhere gained. The army surgeons who 
have been working on the subject of mosquitoes and 
yellow fever have shown, as, in fact, had Dr. Finlay be- 
fore them, that the same mosquito will bite and suck 
blood again and again, and Drs. Reed, Carroll, and Agra- 
monte have demonstrated that the yellow-fever mosquito 
will not convey the disease until at least twelve days 
have elapsed since the time when it bit a yellow-fever 
patient. In the case of Anopheles and malaria there 
must be an interval of seven or eight days for the proper 
development of the malarial organism in the body of the 
mosquito, before the disease can be conveyed through a 12 
MOSQUITOES 
puncture to a healthy individual. The best we can do, 
then, is to say that the adult mosquitoes live indefinitely 
—certainly, under favorable circumstances, even in sum- 
mer, for several weeks—and that they may bite an indef- 
inite number of times. 
Observations by Fermi and Lumbao on Culex pipiens in 
Italy led them to believe that this mosquito, after emerg- 
ing, devotes itself to blood-sucking and similar pleasant 
occupations, but that egg-laying only takes place after 
from fifteen to twenty days, and that after egg-laying the 
females die. This observation may be perfectly correct, 
but it is contrary to the customary rule with insects, since 
it is almost a law that after the issuing of the adults the 
first and main business of life is the perpetuation of the 
species. 
Transformations of Mosquitoes Artificially Hastened. 
Iii the summer of 1900, while engaged in making experi- 
ments as to the insecticidal effect of creosote-oil poured 
upon the surface of water in breeding-jars containing 
mosquito larvae, I made what seems to me to be a most 
interesting observation. In one battery jar containing 
three quarts of water, eighty nearly full grown larvae of 
Culex stimulans and C. perturbam were placed, and one- 
fourtli of an ounce of creosote-oil of a specific gravity 1.035 
at G0° F. was poured. This was jar No. 1. In another 
jar were two quarts of water in which were placed 150 
larvae of the same species, all full grown or nearly so. 
Upon this water, three-sixteenths of an ounce of a sonie- MOSQUITOES IN GENERAL 
13 
what heavier creosote oil was poured. This was jar No. 2. 
When at 4.15 p.m. the creosote was poured in jars 1 and 2, 
no pupae were observed, but all larvae were full grown or 
nearly so. After fifteen minutes ten pupae were observed 
in jar 2 and live in jar 1. Ten minutes later fifteen were 
counted in jar 2 and thirteen in jar 1. Twenty minutes 
later there were nineteen in jar 2 and twenty-two in jar 
1. Fifteen minutes later still there were nineteen in jar 2 
and twenty-two in jar 1. Thirty minutes later there were 
seventeen in jar 2 (two having died in the interval) and 
twenty-eight in jar 1. As above stated, over night a num- 
ber of adults issued, ten in jar 1 and eight in jar 2, and 
twenty-four hours later ten more adults issued in jar 1. 
It must be remarked that the full grown larvae struggled 
violently on perceiving the uncomfortable presence of the 
creosote, and as they were just ready to transform, this 
violent struggling evidently assisted in the breaking of 
the larval skin, leaving the pupa bare. This transforma- 
tion from larva to pupa is hardly as interesting as the 
rapid development of adults, eighteen of which issued 
within fifteen hours after transformation to pupa, whereas 
previously the shortest duration of the pupal state which 
we had observed was forty-eight hours. It looks like an 
effort of nature to perpetuate the species in the presence 
of a unique emergency. 
Mosquito Songs. 
Probably owing to an association of ideas, the curious 
sound made by mosquitoes as they approach one’s ear is 14 
MOSQUITOES 
to most people extremely irritating. This faint sound 
will waken many from the soundest sleep. It is not loud, 
and in quality may perhaps best be compared to the dis- 
tant note of a bagpipe. The sound is apparently pro- 
duced, as with flies and other dipterous insects, not by 
the rapid vibration of the wings, but by the vibrations of 
a chitinous process in the large tracheae just behind the 
thoracic spiracles. These vibrations are produced by the 
air during respiration. Dragon-flies and bees, as well as 
flies, sing in this way. With bees, however, the rapid 
vibration of the wings causes another hum, and the two 
notes are most readily distinguished, the wing tone of the 
honey bee being A', while the breathing voice is at least 
an octave higher, and sometimes nine or ten full tones 
higher, going to B" and C". The exact musical note of 
the different species of mosquitoes seems not to have been 
investigated, but as long ago as 1874, A. M. Mayer, in the 
course of his researches in acoustics, made some most in- 
teresting experiments with the supposed auditory appa- 
ratus of some species of Culex, which, unfortunately, was 
not named. Mayer established the fact that some of the 
antennal hairs of the male mosquito are auditory. With 
tuning-fork experiments he showed that some of the hairs 
are especially tuned so as to respond to vibrations num- 
bering 512 per second. Other hairs vibrated to other 
notes. He also experimented with the song of the female, 
and showed that the auditory hairs of the male antennae 
vibrate when the song of the female comes at right angles 
to them. If the song is directly in front of the head it 
will be most fully perceived by the hairs. If the song of MOSQUITOES IN GENERAL 
15 
the female affects one antenna more than the other, the 
male turns his head until both antennae are affected, and 
is thus able to determine the exact direction of the female, 
to which he then flies. Mayer found that the male can 
thus guide himself to within five degrees of the exact 
direction of the female. His conclusion is that “ these 
insects must have the faculty of the perception of the 
direction of sound more highly developed than in any 
other class of animals.” Mayer carried his experiments 
farther, and made large wooden models of the hairs, with 
which he conducted interesting experiments. His paper 
is published in full in the American Journal of Science 
and Arts, vol. viii. (1874), pages 89-103, and should be 
read by those interested in this subject. 
Recently, Mr. A. DeP. Weaver, an electrical engineer 
of Jackson, Miss., wrote me that while engaged in some 
experiments in harmonic telegraphy, in which a musical 
note of a certain pitch was produced by electrical means, 
he was amazed to find that when the note was raised to a 
certain number of vibrations per second, all mosquitoes, 
not only in the room where the apparatus was, but also 
from other parts and from outside, would congregate 
near the apparatus and would be precipitated from the 
air with astonishing force, striking their bodies against 
the apparatus. He states that he therefore covered a 
large surface with sticky fly-paper and after sounding the 
note for a few seconds captured all the mosquitoes in the 
vicinity. He then devised an apparatus to electrocute 
them. A section of wire window screen with the paint 
removed was mounted on a board and small pins were 16 
MOSQUITOES 
driven between the meshes, the heads coming flush with 
the surface of the screen. All the pins were connected 
together electrically, the whole forming one electrode of 
the secondary coil of an induction coil, while the wire 
screen formed the other electrode. An alternating cur- 
rent of high potential was then passed and when the 
note was sounded the insects precipitated themselves 
against the screen and were immediately electrocuted. 
Mr. Weaver, unfortunately, does not state whether males 
only were captured in this way. His letter was an 
extremely interesting one, and surely his sticky fly-paper 
experiment suggests that further experimentation in this 
direction would be worth while. 
Apropos to the difference in the musical note of differ- 
ent kinds of mosquitoes it should here be stated that, as 
will be pointed out in our consideration of the malaria- 
bearing mosquitoes of the genus Anopheles, the sound 
made by the female Anopheles is distinctly lower in 
pitch than that made by the less harmful mosquitoes of 
the genus Culex. An interesting parallel to this is the 
fact that the villain in the play has usually a bass voice! 
How Far do Mosquitoes Fly? Are They Carried by 
Winds? 
A very important point to be considered by persons 
who are engaged in extermination work against mosqui- 
toes is the one suggested by the heading of this section. 
To the owner of a large estate it is most discouraging to 
anticipate that at the close of careful remedial work, in MOSQUITOES IN GENERAL 
17 
which the drainage of breeding-places and kerosening of 
breeding-pools has been carried on, hungry swarms of 
mosquitoes may fly in from a distance or may be carried 
in by winds, to camp upon his grounds and in his house 
and renew the annoyance of the irritating punctures, and 
perhaps even to seek out some neglected breeding-place 
and start new generations. Therefore the question of the 
length of flight is a most important one. In the summer 
of 1900, Mr. W. J. Matheson, living at Lloyd’s Neck, Long 
Island, a spot formerly infested by mosquitoes to an ex- 
traordinary degree, by intelligent exterminative measures 
succeeded in practically stopping the breeding of mos- 
quitoes upon this rather narrow neck of land. It resulted 
that his house was mosquito-free until toward the end of 
August. Then, after a gentle and continuous wind of 
two or three days’ duration, specimens of another kind of 
mosquito put in their appearance in large numbers. 
The explanation was obvious. These mosquitoes had 
flown across a strip of water forming one of the entrances 
from Long Island Sound to Oyster Bay, for a distance of 
a mile or a little more, aided by the gentle and continu- 
ous wind. 
This incident points out an important condition of 
affairs. Ordinarily, it may safely be said that mosqui- 
toes do not tiy far. Where there is water favorable for 
egg-laying- in the immediate vicinity of the place of their 
birth, and especially where there are warm-blooded ani- 
mals upon which they may feed, they have no migratory 
incentive. Then again, they are not strong fliers, as in- 
sects go. It seems perfectly certain, from the evidence 18 
MOSQUITOES 
which has been collected, and especially by that adduced 
by Mrs. C. B. Aaron in her essay in the little book en- 
titled “ Dragon-tlies versus Mosquitoes” (The Lamborn 
Essays, Appleton & Co., 1890), that mosquitoes are very 
careful not to take wing during a strong breeze. Mrs. 
Aaron’s words are worth quoting: 
The migration of mosquitoes lias been the source of much mis- 
apprehension on the part of the public. The idea prevalent at 
our seaside resorts that a land breeze brings the swarms of mos- 
quitoes from far inland, is based on the supposition that this in- 
sect is capable of long-sustained flight and a certain amount of 
battling against the wind. This is an error. Mosquitoes are 
frail of wing ; a light puff of breath will illustrate this by hurl- 
ing the helpless creature away, and it will not venture on the 
wing again for some time after finding a safe harbor. The preva- 
lence of mosquitoes during a land breeze is easily explained. It is 
usually only during the lulls in the wind at such times, that 
Culex can fly. Generally on our coast a sea-breeze means a stiff 
breeze, and during these even the Odonata, and often the robust 
and venturesome Tabanidse, will be found hovering on the lee- 
ward side of the houses, sand-dunes, and thick foliage. In the 
meadows south of Atlantic City, N. J., large swarms of Culex are 
sheltered in the dense grass or wind-battered tree-tops on the off 
side of the sand-dunes. Here, in common with all localities so 
exposed to searching wind, the trees and large bushes are much 
stunted in growth and battered down to a flat top and common 
level by the wind. In these matted branches, dense with the 
close-clustered foliage, the mosquitoes may be discovered in such 
numbers as to bring despair to the heart of the student who is 
plotting their final extermination. While the strong breezes last, 
Culex will stick close to these friendly shelters, though a cluster MOSQUITOES IN GENERAL 
19 
of houses may be but a few rods off, filled with unsuspecting mor- 
tals who imagine their tormentors are far inland over the salt 
meadows. But if the wind dies down, as it usually does when 
veering, out come swarms upon swarms of the females, intent 
upon satisfying their depraved taste for blood. This explains 
why they appear on the field of action almost immediately after 
the cessation in the strong breeze ; on the supposition that they 
were blown far inland, this sudden reappearance would be un- 
accountable. 
Many observations made by the writer and by his cor- 
respondents support these views which Mrs. Aaron has 
expressed. Mr. W. C. Kerr, of Staten Island, an excellent 
observer, is strongly of the opinion that mosquitoes are 
not blown over from New Jersey to Staten Island. Pro- 
fessor Herbert Osborn, formerly of Ames, la., has noticed 
that in dry seasons small pools within a quarter to a half a 
mile from the college buildings at Ames, dry up, and the 
mosquitoes disappear, in spite of the fact that within 
about a mile there are large pools which never become 
dry. One of my former assistants, Mr. R. M. Reese, 
found in Baltimore that by treating breeding-places a hun- 
dred feet or a little more from his house with kerosene, 
the supply of mosquitoes in his house was greatly re- 
duced, although there were many other breeding-places 
only twice as far away. Dr. John B. Smith, a well known 
entomologist, has recorded his observation that mosqui- 
toes will not rise or take flight when a brisk breeze is 
blowing, and that even a comparatively slight breeze will 
keep them from the upper stories of houses. 
Dr. H. T. Fernald, however, after several summers’ 20 
MOSQUITOES 
work at the Cold Spring Harbor Laboratory, on Long 
Island, has stated that with a south breeze, especially 
after a prolonged and gentle wind of five or more hours’ 
duration, mosquitoes become very troublesome and it is 
the local supposition that they are carried from the south 
shore of Long Island, fifteen miles away. This is, the 
writer finds, the general opinion at several points on the 
north shore of Long Island, but observations which he 
has made on the mosquito topography of that portion of 
the island have shown that there are usually many breed- 
ing-places much nearer than the south shore, and usually 
quite near the infested places, which will much more 
easily account for the mosquito supply. In fact, careful 
observations made by Mr. H- C. Weeks, of Bay side, Long 
Island, have shown that in the immediate vicinity of the 
Cold Spring Harbor laboratories there are many breed- 
ing-places of such extent and such capacity as to indicate 
that the south shore theory must be abandoned. 
So many instances, in fact, liave come to my attention, 
where extensive breeding-places profusely stocked with 
mosquito larvae have been overlooked by the people of 
given neighborhoods, that I have, as a general rule, be- 
come more or less incredulous on the subject of extended 
mosquito flights. Fermi and Lumbao, in their report on 
operations in Sassari, state that the mosquitoes of the city 
do not go far from their original breeding-grounds, since 
they find sufficient food near the habitations of people 
and animals. The reason which the Italian authors give 
for this absence of migration may be correct or incorrect, 
but their experience has shown that where a house 1 oca- MOSQUITOES IN GENERAL 
21 
ted near the centre of a city or village is found to be in- 
fested by mosquitoes, search for the larvae should be 
made in the house or near it, particularly in cellars or 
cisterns, in wells, in water-troughs, in sinks and tubs in 
the yard, and so on. The truth is that people do not take 
the trouble to make the careful search, and prefer to jump 
to the conclusion that the mosquitoes have Hoavii in upon 
them from a distance. Mr. C. A. Sperry, of Chicago, 
writes that he is perfectly satisfied that mosquitoes are 
never distributed by the wind. When the wind blows they 
are always on the ground, clinging to a support. They 
are seldom, if ever, seen as high as the third flat in the 
city. He further makes the suggestion that the idea that 
they are conveyed by the wind deters many people from 
making an effort to rid themselves of the nuisance, which 
can so easily be accomplished. In one case, at a summer- 
resort on Long Island, a man told him that the mosqui- 
toes came there from New Jersey, while not two hundred 
yards from his house was a pool that in Mr. Sperry’s 
opinion produced all the mosquitoes that were such a 
troublesome pest and drove hundreds away from his place. 
Mr. Sperry is a close observer of mosquitoes and has 
studied them for years. 
Dr. C. W. Stiles, of Washington, however, is inclined 
to take a somewhat opposite view from Mrs. Aaron. He 
informs me that it has been his experience, at his summer 
cottage on the New Jersey coast, that mosquitoes bother 
his family onty after land breezes have continued for sev- 
eral days. The cottage is situated about one-third of a 
mile away from the woods, toward the sea and within one MOSQUITOES 
22 
hundred yards of the surf. As it is absolutely isolated 
from trees, and as the mosquitoes do not appear during 
a lull in the breeze, but only after several days of land 
breeze, it appears to him that the popular view of the 
influence of land breezes upon spreading mosquitoes sea- 
ward is not wholly without foundation. 
All tlie evidence so far adduced refers to more or less 
normal conditions and, in fact, such conditions are the 
only ones which need practically be considered. Under 
very exceptional conditions, however, it seems perfectly 
plain that mosquitoes may migrate for considerable dis- 
tances ; two such instances are described in the following- 
lines quoted from a recent letter received from the Hon- 
orable J. D. Mitchell, of Victoria, Tex., a reliable ob- 
server and a naturalist. 
. . . I have witnessed, in my life, two migrations of mos- 
quitoes, that will always be fresh and vivid in my memory. 
Where the Colorado River empties into Matagorda Bay, a 
marsh is formed over the lowlands, by a raft in the river ; this 
marsh contains about eighteen square miles, and is a magnifi- 
cent breeding-place for mosquitoes. 
I used to ranch it on the peninsula-like body of land, formed 
by Carancaliua Bay on the east, Matagorda Bay on the south, 
Keller’s Bay and Creek on the west, and the Calhoun County 
north line on the north (refer to coast maps of Texas). The dis- 
tance between my ranch property and the marsh above described 
is, by bay route, about forty miles ; the way the crow flies, about 
thirty-five miles. My ranch was situated on Carancaliua Bay, 
near the north end of land. 
The first migration occurred in October, 1879. There had been 
an overflow from the upper country, which lilled the aforesaid MOSQUITOES IN GENERAL 
23 
marsh, but the balance of that section was very dry and needing 
rain, and there were no mosquitoes. A fairly strong easterly wind 
had been blowing for three days ; on the evening of the third day 
the mosquitoes arrived, flying high, about fifty feet, and looking 
like a cloud or mist coming over Carancahua Bay. At the ranch 
they set everything on fire that had blood in it, and all work was 
suspended by unanimous consent. Cattle and horses rounded-up 
milled continuously ; all work stock was turned loose as quick as 
possible and they went to the round-ups at full speed, and little 
or nothing was done for nearly five days ; by this time the main 
body had passed, though plenty remained to make everything 
uncomfortable for about two weeks. This migration was from 
east to west and the line was about three miles wide—above and 
below this there were no mosquitoes. 
Migration No. 2 occurred in October, 1886. They came from 
the same marsh before described—this migration confined itself 
to the Matagorda Bay shore line, reaching inland about half a 
mile ; there were as many mosquitoes in this limit as there were in 
the three miles of migration No. 1. They clouded the sky, bent 
down the grass with their weight, and made all driftwood and 
ground the same color. All stock left the shore and went north 
outside of the line of marsh. The wind was light and from the 
south, and did not affect the mosquitoes in their flight, which was 
westward ; the main flight was low, ten or twelve feet high and 
always in the same direction. With three other men I rode into 
the swarm to a large pile of drift and trash and set it on fire, and 
stood in the smoke for some time watching them. They passed 
sometime during the third day, leaving very few stragglers be- 
hind. By inquiry, 1 traced both of these swarms from the marsh 
before described to fifteen or twenty miles west of my ranch, a 
total distance, air line, of fifty or sixty miles. 
No. 1 crossed Trupalacios Bay, where it was five miles wide, and 
Carancahua Bay, where it was one mile wide. No. 2 holding to MOSQUITOES 
24 
the shore line, crossed Trupalacios Bay, three miles, Carancahua 
Bay, at Pass, 300 yards, Keller’s Bay, at Pass, half mile, Cox’s 
Bay, one and a half miles, and Port Lavaca Bay, four miles. 
It may incidentally be stated that malarial mosquitoes 
of the genus Anopheles seem much less capable of ex- 
tended flight than the commoner mosquitoes of the genus 
Culex. Dr. F. A. Young, of the British Army Medical 
Service, on his way home from Shanghai, where he had 
been conducting experimental work against malarial mos- 
quitoes, called on me in February, 1901, and stated that 
it was his firm conclusion that, as a rule, Anopheles will 
not fly over two hundred yards, and that a breeding-place 
more than two hundred yards from the house will not 
supply malarial mosquitoes to that house, provided there 
are other houses nearer. He mentioned a number of cir- 
cumstantial instances supporting this view. Christo- 
phers and Stephens, however, in their reports on the 
malarial expedition to Sierra Leone, state that it is cer- 
tain that under some circumstances Anopheles may fly 
much greater distances than has been supposed. In one 
small inland house which had been occupied by one old 
man, five or six Anopheles were to be caught each morn- 
ing. These were freshly hatched and could only be de- 
rived from a breeding-place three to four hundred yards 
away. In another place the same writers show a flight 
of six hundred yards. But, after all, what are even six 
hundred yards ? In an effort to free a locality from ma- 
laria such distances become insignificant. 
On the whole, it seems to the writer that in almost no MOSQUITOES IN GENERAL 
25 
cases need an individual or a community be deterred 
even for a moment from attempting remedial work 
against mosquitoes by the idea that the mosquito supply 
is likely frequently to be renewed by flights from long 
distances or even from distances of much more than a 
single mile. A far more serious source of re-establish- 
ment of the mosquito supply will be considered in the 
following section. 
Carriage of Mosquitoes by Bailway Trains and other 
Conveyances. 
Tliat mosquitoes are carried by railway trains must be 
a matter of common observation to everyone who travels. 
That this method of distribution is and has been a very 
important one, has, however, been rather generally over- 
looked. It is said that mosquitoes were unknown in 
Hawaii until brought over in sailing vessels from the 
United States. On these sailing vessels they had proba- 
bly bred more or less continuously in the water-barrels, 
and when once introduced into the islands they bred with 
great facility in the swamps and fresh water ponds, and 
to-day these insects are said to be very abundant there. 
Beyond the statement which occurs in Nuttall’s mono- 
graph (1899), where the probable influence of winds, rail- 
ways, and ships in the dissemination of mosquitoes is 
briefly mentioned, the subject had received practically no 
consideration until it was brought out in the bulletin en- 
titled, “ Notes on Mosquitoes,” prepared by the author 
and published by the United States Department of Agri- 26 
MOSQUITOES 
culture, in August, 1900. It was there stated that by 
means of railway trains unlimited quantities of mosqui- 
toes are carried unlimited distances, and on emerging 
from the cars they start to breed, even where mosquitoes 
are ordinarily rare, or would be rare under ordinary con- 
ditions. In this way, even mountain-resorts were said to 
get their supply of lowland mosquitoes, and the con- 
stantly increasing danger of this method of distribution, 
through the perfection of the railway service and the in- 
crease in the number of through cars, was pointed out. 
It was shown that although the State of New Jersey, as 
an example, has a bad mosquito reputation, that does not 
necessarily mean that there are any more breeding-places 
in the interior of the State, or that New Jersey mosqui- 
toes are any more prolific than elsewhere. The constant 
abundance of mosquitoes in New Jersey seemed to the 
writer to be dependent upon the fact that the coast is 
lined by many swamps, and that all through the summer 
evenings many trains are started inland from nearly a 
dozen points on the coast, from Weehawken to Cape 
May. These trains may contain mosquitoes by the hun- 
dreds, and at every stop they may fly from the cars and 
seek breeding-places near the railway. 
A discouraging feature of this method of spread is that 
although exterminative work of the most thorough char- 
acter may be carried on in any locality near a railroad, 
new supplies of mosquitoes are constantly being brought 
in and will begin to breed wherever water can be found. 
I called attention to the fact that in the Catskill Moun- 
tains one place which had come under my observation MOSQUITOES IN GENE UAL 
27 
was free from mosquitoes, until through cars on the 
railroads brought them up from the vicinity of New York 
City. 
After the publication of this bulletin some doubt was 
expressed by the newspaper reviewers of the importance 
of this method of dissemination ; but confirmatory evi- 
dence of a striking character has since been gained, al- 
though, as a matter of fact, the proposition was so self- 
evident that it did not need confirmation. The interest- 
ing community work undertaken against mosquitoes by 
the city of Winchester, Ya., and which will be referred to 
in detail in the chapter on remedies, has brought out the 
fact that Winchester Avas at one time a favorite summer- 
resort, and that mosquitoes were practically unknown, but 
that with the establishment of a night train on the Balti- 
more & Ohio Railroad, running from Camden Station, 
Baltimore, in the summer-time, mosquitoes began to be a 
positive annoyance in Winchester. Unfortunately, with 
the establishment of this night train, or about the same 
time, Winchester extended its system of water-works and 
did not build sewers. As a result, with the arrival of the 
mosquitoes from Baltimore there was a plentiful supply 
of standing water all through the city, and conditions 
were thus perfect for the development of mosquitoes in 
enormous numbers. 
Mr. C. A. Sperry, of Chicago, who formerly lived in 
Mexico, lias informed me that in the City of Mexico, be- 
fore the railroads were built to Tampico and Vera Cruz, 
there were no mosquitoes. They were brought up from 
the coast, however, in the cars, and established tliern- MOSQUITOES 
28 
selves there. Tampico and Vera Cruz, both low-lying 
cities, had always had mosquitoes in numbers. The City 
of Mexico, lying on a table-land 7,000 feet above the sea- 
level, and with a cool and pleasant climate, having no 
mosquitoes, thus with the addition of railroad facilities 
became infested. 
Mr. C. P. Lounsbury, government entomologist of the 
Cape of Good Hope (in litt.), is responsible for the state- 
ment that the railroads in Cape Colony have been re- 
sponsible for taking mosquitoes to many inland towns 
which before the advent of the iron horse were quite free 
from the pest. Another correspondent gives the details 
of a precisely similar introduction of mosquitoes into a 
high-lying Missouri town. 
In a similar way, stage-coaches are responsible for the 
spread of mosquitoes. Grassi, the Italian investigator, 
states that he counted two hundred specimens of Anoph- 
eles on the inside of a coach, during a drive lasting two 
hours through the plains of Capaccio, and the same 
observer has recorded the capture of malarial mosquitoes 
in a railway carriage travelling from Florence to Berlin. 
Queer Places in which Mosquitoes Breed. 
Iii the report of the Liverpool School of Tropical Medi- 
cine’s Malaria Expedition to Sierra Leone, it is stated 
that mosquitoes were found breeding- in the broken bot- 
tles which were placed upon the top of a stone wall to 
act as a cheval de /rise, and that they were found also 
breeding in the flower vases on the tables in the houses MOSQUITOES IN GENERAL 
29 
of European residents, the servants having conscien- 
tiously changed the flowers every morning, but with a cor- 
responding lack of conscientiousness omitted to change 
the water. I have found them breeding in an old tin to- 
mato-can on the dumps in Washington. Mr. W. E. Seal, 
of Delair, N. J., writes that he finds the larvae of mos- 
quitoes in rain-filled hollows in apple, maple, and other 
trees, often at a considerable distance from the ground. 
Mr. Pratt has found them breeding in a hollow stump 
near Bladensburg. Mr. Pergande has shown that they 
breed in the closed sewers in Washington, entering 
through the perforated sewer-traps and emerging through 
the same holes. Mr. Matheson showed me an old disused 
well which was covered with a board cover, but on lifting 
the cover mosquitoes were found roosting on the under 
side in large numbers. There was a crack in the cover 
sufficiently large to admit them, and they smelled the 
water below, worked their way through the crack and 
bred in the old well. They will breed in all water-tanks, 
and the cover must be absolutely tight, since gravid fe- 
males are so strongly attracted by water that they will 
work through a crack which seems almost too small to 
admit their bodies. Dr. John B. Smith says that they 
are found in New Jersey in great numbers in the pitchers 
of the pitcher plants of the genus Sarracenia. 
These statements refer for the most part, if not entirely, 
to the common mosquitoes of the genus Culex, which we 
assume to be comparatively harmless from the disease- 
carrying standpoint, but they indicate plainly that where 
one’s object is to rid a house or a neighborhood of mos- 30 
MOSQUITOES 
quitoes, in order to avoid their irritating punctures and 
to produce the condition of general comfort which the ab- 
sence of mosquitoes brings, no possible spot where water 
can accumulate should be overlooked. The smallest pos- 
sible collections of stagnant rain-water become breeding 
places and may swarm with larvae. Mr. E. E. Austin, of the 
Liverpool Tropical School Expedition, has seen in AVest 
Africa that discarded bottles, Swiss milk and sardine tins, 
and cocoanut husks, frequently swarm with larvae, while 
the water which accumulates in disused calabashes and 
other vessels lying about outside of houses is used for 
breeding. Mr. It. H. Pettit (Bui. 18G, Mich. xA.gric. Col- 
lege Exp. Sta.), in a report on “ The Insects of the Upper 
Peninsula of Michigan,” writes as follows: “ Land that is 
being cleared furnishes an ideal place for them to breed. 
Holes made in removing stumps and into which water 
has settled are often fairly alive with wrigglers.” He 
collected a large number of larvae and pup® from a hole 
which would hold only a small quantity of water, and 
bred adults from them. 
AVe lnive mentioned above that Dr. Smith has found 
them breeding in the pitchers of the pitcher plant, and 
Dr. Henry Strahan, in the Journal of Tropical Medicine 
for August, 1900, shows that mosquitoes breed in Lagos, 
West Africa, in similar plants. In the summer of 1900, 
Mr. AV. J. Matlieson, of Lloyd’s Neck, Long Island, after 
a most successful work, which included the drainage or 
treatment with kerosene of every possible ascertained 
breeding-place within a half mile or more of his house, 
in October, on going into his greenhouse, noticed three or MOSQUITOES IN GENERAL 
31 
four mosquitoes, and on looking around for their breeding- 
place he discovered it in a tank at the corner of the 
greenhouse, in which the gardener was in the habit of 
keeping from thirty to forty gallons of cistern water, in 
order that it might be of the temperature of the green- 
house. The tank was apparently full of mosquito larvae. 
On measuring out in a quart jar, and counting them, Mr. 
Matheson estimated that there were probably in the neigh- 
borhood of three thousand larvae. This is a very inter- 
esting instance as illustrating the point upon which we 
have just insisted, since, after the exterminating work 
which had been done, these three thousand mosquitoes 
would have caused considerable annoyance to the house- 
hold, and might have given rise to the opinion that they 
had flown in from an unknown distance. 
Mr. H. C. Weeks, in the Scientific American Supplement 
for January, 1900, very forcibly puts one aspect of mos- 
quito breeding in the following words: “. . . a care- 
ful supervision by those whose study of the subject 
quickly enables them to detect the dangers from old 
sources, as well as from new ones arising from constantly 
changing conditions, especially about the towns — the 
building of a railroad, the making of a drive, the block- 
ing of an outlet to water by the washings of a storm or 
the falling in of some excavated materials, the building 
of a new house wdiose waste water is' not properly cared 
for, these and a hundred others are exigencies which re- 
quire an interest in the subject and a careful and minute 
watchfulness.” 
Mr. Pergande’s interesting- discovery that they breed 32 
MOSQUITOES 
in the closed sewers in Washington, deserves more de- 
tailed mention than Ave have given it. His house in 
northeast Washington being infested with mosquitoes 
and no exposed standing water occurring in the vicinity, 
he thought of covering the small perforated sewer-trap 
in his back yard Avitli a Avire screen. To prevent the pos- 
sibility of mosquitoes entering the screen from the out- 
side, a layer of cotton Avas placed around the edge of the 
trap on Avhicli the screen rested. On August 24th tAvo 
females of Calex pungens Avere found under the screen. 
September 3d another Avas found in the same place, but 
it Avent back to the seAver as soon as the rays of the sun 
struck the screen. September 6th, 10th, and lltli, five 
more were caught. Female mosquitoes in search of 
breeding-places had evidently floAvn through the seAver- 
trap perforations, had found standing Avater in the seAver 
and laid their eggs, from which a generation of adults 
Avas developed. 
There are other localities in Washington, far removed 
from the Potomac lliver front, where mosquitoes are more 
or less abundant, and where there seems to be no standing 
water in which they can breed. It therefore seems rea- 
sonably sure that this sewer-breeding may be rather com- 
mon in certain cities where the general slope is so slight 
that the water may almost stand still for a few days, in 
the absence of very heavy rains which flush the sewers. Of 
course such breeding will easily be stopped by a little 
neighborhood Avork, either by occasionally pouring a little 
kerosene down the seAver-traps or by covering them with 
a wire screen, as did Mr. Pergande in his experiments. MOSQUITOES IN GENERAL 
33 
Another instance of the necessity of searching out of 
the way places for mosquitoes and larvae has recently 
been told me by Dr. James Carroll, U. S. A., a member of 
the Yellow-fever Commission. Visiting an army officer in 
charge of a post in Cuba, he found the yellow-fever mos- 
quito in numbers in the quarters. The officer in charge 
could not imagine where they came from, as, under orders, 
he had had every possible breeding-place exterminated, 
either by surface drainage or by petrolizing. Dr. Carroll 
noticed that the table in the dining-room had been insu- 
lated by placing its legs in small jars of water, the surface 
of the water being carefully covered with kerosene. In 
going into an adjoining room, however, he found that a 
table there had also been insulated in the same way, but 
that the water about only one of the legs of the table had 
been covered with kerosene, while the jars under the 
other three legs were swarming with mosquito larvae. 
This was the fault of the orderly, an Irishman, who liter- 
ally obeyed orders in kerosening such vessels as had been 
pointed out to him, but no more. Enough mosquitoes 
bred in these three jars to stock a large community. 
It is common opinion that mosquitoes do not need 
standing- water in which to breed. It is generally sup- 
posed by non-observant people that they are able to breed 
in wet grass, and it is a common observation, as recently 
expressed by a correspondent of the Pacific Rural Press 
of San Francisco, that mosquitoes are more abundant 
about well watered lawns than in vacant lots, with the 
dry, sandy surface which they naturally have in a dry 
summer season. But there is not the slightest evidence 34 
MOSQUITOES 
that any such condition of affairs can exist. In such 
cases as that described by the Californian, the mosquitoes 
are naturally attracted by the moist air. They search for 
breeding-places, and are attracted by moisture, however 
slight; and then, too, it is well known that they drink 
water, and while the drops on the grass-blades will not 
induce them to lay eggs, they can readily fill their stom- 
achs in the absence of the more highly nutritive liquid 
known as human blood. Some men drink water instead 
of beer, but it is a sad fact that no mosquito is ever known 
to drink water when she can get blood. In the California 
case, the humidity of the air around the sprinkled lawn 
pleased the mosquitoes better than the dry air of the 
vacant lots, and in the face of the multifarious and unob- 
served opportunities for the collection of small quantities 
of water, many of which we have just indicated, there will 
always be found some explanation for mosquito abun- 
dance, other than that they will breed in wet grass. There 
is this to be said, however, as has been pointed out more 
fully in another paragraph, that in dry seasons mosqui- 
toes will live until the rains come, and this is especially 
true of pregnant females. Nature cares for the perpetua- 
tion of the species, and in some way provides for the ex- 
istence of individuals until the perpetuation of the spe- 
cies is assured. 
Food of Adult Mosquitoes. 
With little doubt it is only the females of mosquitoes 
which draw blood, and with as little doubt female mosqui- 
toes are normally plant-feeders. When we consider the MOSQUITOES IN GENERAL 
35 
enormous numbers in which mosquitoes occur, it is safe 
to say that only an infinitesimal proportion of them ever 
taste the blood of a warm-blooded animal. They have 
been seen with their beaks inserted into juicy plants; 
they have been observed sucking ripe fruit, watermelons, 
and even boiled potatoes. There are in this country 
great tracts of marshy lands into which warm-blooded 
animals never find their way, and in which mosquitoes 
are breeding in countless numbers. 
But they are not confined to plants and warm-blooded 
animals. They attack other insects, although observa- 
tions on this point are not common. Dr. H. A. Yeazie, 
of New Orleans, informs me, however, that he has seen 
mosquitoes stinging the Cicada, or “ locust,” as it is in- 
correctly called, and also the soft skinned pupa of the 
same insect. Dr. H. A. Hagen has recorded an observa- 
tion where he saw a mosquito in the Northwest engaged 
in feeding on the chrysalis of a butterfly. Cold-blooded 
vertebrates are also attacked. Mr. J. Turner Brakeley, of 
Hornerstown, N. J., writes that he has seen a black ter- 
rapin surrounded by a swarm of mosquitoes, but that she 
paid no attention to them, possibly because she was en- 
gaged in egg-laying. Moreover, there are several in- 
stances on record in which mosquitoes have been seen 
puncturing the heads of young fish. That mosquitoes 
suck the blood of birds is also well proven. In the course 
of Boss’s original observations in India with a malarial 
disease of sparrows, he had no difficulty in inducing 
mosquitoes to bite these birds, and a recent correspond- 
ent of the Baltimore Sun nearly lost some pet canaries 36 
MOSQUITOES 
through the bites of mosquitoes, which seemed especially 
attracted to these birds. 
To revert once more to the plant-feeding habit, persons 
engaged in the study of malarial relations of mosquitoes 
have found that they feed readily upon fruit, and bananas 
are a favored article of diet. Dr. John B. Smith, of Rut- 
gers College, informs me that he has seen males and 
females of what is probably Culex sollicitans attracted 
by the blossoms of wild cherry, and appear to dig into 
the centre of the blossom, at Anglesea, N. J. So abun- 
dant Avere they that he captured hundreds by sweeping his 
net over the blossoms. 
The male mosquito seems to be exclusively vegetarian 
in its diet. The beak in this sex is weaker, and does not 
seem fitted for the penetration of the skin of even a 
tender-skinned animal. Its food it probably chiefly 
gained by sipping exposed liquids. They are often 
seen sucking at drops of water or molasses, or beer, or 
wine. Dr. St. George Gray, of St. Lucia, British West 
Indies, finds that down there he can almost daily catch 
one or two males on the neck of a decanter, or in a wine- 
glass that has just been used. He has made some inter- 
esting observations on the intoxicating effect of wine 
upon the males. It appears from these observations and 
the beer-drinking habit of the males, as observed by 
Schwarz, that in any discussion of sex habits into which 
the mosquito may be lugged as an example that blood- 
thirstiness may exist in the female sex, this statement 
may be offset by the fact that even with this creature the 
male sex is the one that is prone to alcoholism. MOSQUITOES IN GENERAL 
37 
In spite of what wre have just said about the non-pene- 
trating mouth parts of male mosquitoes, Dr. C. W. Stiles 
informs me that he and Hurst (the author of an im- 
portant paper on the pupal stage of Culex, Manchester, 
1890) made an observation in the summer of 1889, at Leip- 
sic, which convinced him that either the males do oc- 
casionally bite or that occasionally females possess 
feathered antennae. Stiles and Hurst wrere out in a row- 
boat one evening and were bitten a number of times by 
Culex nemoralis. One individual which bit Stiles on the 
left hand was crushed, and in the crushing act a consider- 
able quantity of blood exuded—enough to make a fair- 
sized blood stain on his skin. Upon examining the dead 
body he was surprised to note that it possessed male an- 
tennae. Hurst also examined it, and remarked that it was 
the first instance he had known where a male Culex had 
actually been caught sucking blood. Dr. Stiles tells me 
that Hurst intended to place the observation on record, 
but that he does not think it was ever published. Dr. 
Stiles is so well known as an accurate observer, that some 
other explanation than faulty observation must be offered 
in this instance. 
This observation, although apparently without pre- 
cedent, leads to a decision coinciding with that of Jor- 
dens (1801), who thought that the male mosquito could 
bite, and wrote, according to Dimmock, “ But since the 
male is also provided with a sucking seta it is not com- 
prehensible why it should not use it for the same pur- 
pose.” Dr. Dimmock, in his admirable dissertation upon 
“ The anatomy of the moutli-parts and of the sucking ap- 38 
MOSQUITOES 
paratus of some Diptera ” (1881), made a most careful 
study of the mouth-parts of both male and female mosqui- 
toes. His conclusions are decidedly against the possibil- 
ity that male mosquitoes can bite warm-blooded animals. 
He says, “ I have tried to have the male mosquitoes bite 
me when in the field where they were abundant, but they 
did not seem attracted, as the female mosquitoes were, to 
my person ; they flew away indifferently without lighting 
upon me. I have often taken male mosquitoes, with all 
possible care to prevent disturbing them, beneath a glass 
cover on my hand, letting them remain long enough to 
be as tranquil as they were when upon the leaves and 
grass of the field, but they would neither bite nor show 
any desire to do so, nor have I been able to feed male 
mosquitoes with water, saliva, or fresh blood, all of which 
liquids the females often drink with avidity. 
“ Upon anatomical grounds, I believe that male mos- 
quitoes take liquid food, although I have never dissected 
their stomachs to see what this food was. They have 
mouth-parts and pharynx developed sufficiently to suck 
liquids; but the absence of barbed maxillae, of a free liv- 
popliarynx, and of oesophageal bulb, leads one to suppose 
that they take a smaller quantity of food than the females 
do, and that they do not obtain it by piercing the skins 
of animals.” 
There is a European species of mosquito, Culex salinus 
Ficalbi, which is said to he diurnal in its habits, and to 
live in salt water, of which the male is said to bite, and 
to possess moutli-parts quite like those of the female. MOSQUITOES IN GENERAL 
39 
Abundance of Mosquitoes. 
In modern times everyone wlio likes out-door life, espe- 
cially men interested in hunting' and fishing, is able to tell 
mosquito stories which rival the somewhat rare instances 
which come down to us from ancient times. 1 have heard 
sportsmen, in fact, vie with each other in describing the 
abundance of mosquitoes in certain localities, but, familiar 
with the tendency of hunters and fishermen to indulge in 
the rhetorical figure known as hyperbole, as evidenced in 
the general acceptance of a specific meaning as applied in 
the expression “ a fish story,” or the adjective “ fishy,” one 
is warranted in a certain measure of disbelief. It is un- 
doubtedly true, however, that certain localities in this 
country are almost uninhabitable because of the great 
numbers of mosquitoes found there, many otherwise 
desirable neighborhoods do noi improve for this reason, 
and some regions are absolutely unsettled on this ac- 
count. Professor E. W. Hilgard, of the University of Cali- 
fornia, has written me that up in northern Washington, 
in the pine forests north of Spokane, the gray mos- 
quito, or Oulex, seems to be the sole possessor of the land, 
and is a fearful nuisance, as in arctic regions. The first 
thing on going into camp is to establish a close line of 
smudges above the wind, so as to enable the pack animals 
and the men to eat in comparative peace, but about mid- 
night the entire swarm is back again. He states that 
there are scattered lakes in that region where they breed, 
but they must migrate considerable distances. He further 40 
MOSQUITOES 
writes that in Montana he has seen all the work horses in 
the field sheathed in sheets during the day, and these were 
dotted with small blood spots. 
An observation made by my colleague, Mr. E. A. 
Schwarz, at Corpus Cliristi, I have had occasion to quote 
several times. He says that at this place, when the wind 
blows from any other direction than south, “hundreds of 
thousands of millions ” of mosquitoes blow in upon the 
town. Great herds of horses run before the mosquitoes in 
order to get to the water, but that with a change of wind 
the mosquitoes disappear. The instance mentioned by 
the Hon. J. I). Mitchell, of Victoria, Texas, and which is 
quoted in the section on “ H ow Far Do Mosquitoes Fly ? ” 
is another indication of the enormous numbers in which 
these insects may occasionally occur, even in localities 
where they are ordinarily not very abundant. 
In olden times, mosquitoes appear to have been quite 
as numerous as they are to-day, and the literature of pop- 
ular entomology contains many instances of the enormous 
numbers in which mosquitoes have occurred in times past. 
In ancient Greece, according1 to Pausanias, inhabitants 
were forced to abandon their homes on account of mos- 
quitoes’ making it impossible for them to remain. Mionte, 
a rich city of Ionia, was abandoned by its inhabitants on 
account of mosquitoes which forced them to flee to Mileta. 
The same thing happened with Pergamo, a beautiful city 
in Asia. Someone has called attention to the fact that 
Theodoretus says that Sapor, King of Persia, was com- 
pelled to raise the siege of Nisibis by a plague of gnats, 
which attacked his elephants and beasts of burden, and MOSQUITOES IN GENERAL 
41 
so caused the rout of liis army. Kirby and Spence say, 
“ In the neighborhood of Crimea the Russian soldiers 
are obliged to sleep in sacks in order to defend themselves 
from the mosquitoes, and even this is not a sufficient se- 
curity, for several of them die in consequence of mortifi- 
cation produced by the bites of these furious bloodsuck- 
ers.” The same writers state that Captain Stedman, in 
America (probably in ante-Revolutionary days), mentions 
that he and his soldiers were forced to sleep with their 
heads thrust into holes in the earth, and their necks 
wrapped around with hammocks, and Humboldt says that 
somewhere in South America the inhabitants pass the 
night buried in sand, which covers them to the depth of 
three or four inches, leaving out only the head, which is 
covered with a cloth. There is even a mosquito story 
which possibly affects the veracity of George Washington! 
Isaac Weld, in his “ Travels through North America, 
1795 1797 ” (London, 1799), in speaking of Skenesborough, 
in northern New York, dilates upon the number and fe- 
rocity of mosquitoes and says, “ General Washington told 
me that he never was so much annoyed by mosquitoes in 
any part of America as in Skenesborough, for that they 
used to bite through the thickest boot.” Now, knowing 
that the boots of those days were very thick, and that the 
mosquitoes of that time must have been structurally iden- 
tical with those of to-day, there arises instantly the ques- 
tion of veracity between Mr. Weld and General Washing- 
ton, and as we know from Dr. Weems’s veracious history 
that General Washington was so constituted that he could 
not tell a lie, it looks very much as though Mr. Weld, like 42 
MOSQUITOES 
certain other travellers who have written books on their 
return home after extended travel, was somewhat inclined 
to overstate the truth. 
Par Northern Mosquitoes. 
As is well known, the mosquito-pest is by no means 
confined to the tropics or even to temperate regions. 
The stories which the returning gold-hunters from 
Dawson City and other Alaskan localities tell of the 
abundance and ferocity of Alaskan mosquitoes, are 
hardly to be matched by any mosquito story which I 
have heard, historical or otherwise. Many of my 
friends in the United States Coast and Geodetic Survey, 
and the United States Geological Survey, who have 
formed members of summer parties for survey work in 
Alaska, have come back to this country with a much 
stronger idea of the importance of the practical study of 
insects than they had when they started, their acquaint- 
ance with mosquitoes having become so intimate and 
their knowledge of their ferocity having reached such a 
pitch that the first question which they ask on returning 
is: “ If I have to go up there next summer, what under 
the sun can I do to keep from being bled to death by 
mosquitoes ? ” They state that they never experienced 
or even imagined anything in the mosquito line quite 
equal to those found in Alaska. Mr. W. C. Henderson, 
of Philadelphia, says, concerning Alaskan mosquitoes, 
“ They existed in countless millions, driving us to the 
verge of suicide or insanity.” MOSQUITOES IN GENERAL 
43 
That mosquitoes should develop in such extraordinary 
numbers in the arctic regions is remarkable when we con- 
sider the extreme brevity of the summer season. Surely 
only a very fewr generations have an opportunity to develop. 
They must therefore hibernate in great numbers even in 
that extreme cold, and their occurrence in this way in such 
localities, when we consider the comparative scarcity of 
mammalian life, indicates in a forcible way how small a 
part the blood of warm-blooded animals plays in the nor- 
mal economy of mosquito life. 
It did not need these recent experiences, however, to 
assure us of the abundance of mosquitoes in arctic regions. 
Kirby and Spence tell extraordinary stories of their 
occurrence in Lapland, where their numbers are said to 
be so prodigious as to be compared to a fall of snow 
when the flakes are thickest, or to the dust of the earth. 
There is a mention of this abundance in the narrative of 
C. F. Hall’s second arctic expedition, and on the Polaris 
Expedition, Dr. Emile Bessels was obliged to interrupt 
his work in the Davis Straits (latitude 72° north) on ac- 
count of the multitude of mosquitoes. 
Iii explanation of these extraordinary numbers—and all 
these stories are unquestionably measurably true—we 
must only think of the universal occurrence of standing- 
water and of the fact that the food required by mosquito 
larvm is very small and very insignificant, consisting 
mainly of the micro-organisms which exist in stagnant 
water, and of the further fact that enormous numbers can 
breed successfully in a very small water supply. As an 
indication of this latter fact, Lugger, in 1896, undertook 44 
MOSQUITOES 
to count the larvae in an ordinary rain-water barrel. On 
July 6th, the water in one barrel was filtered and was 
found to contain 17,259 eggs, larvae and pupae. On July 
22d, 19,110 additional ones were counted. If anyone is 
mathematically inclined, let him assume that half of these 
developed into female mosquitoes, each one of which laid 
400 eggs, and that twelve generations breed in a summer 
in the northern United States. It will then be perfectly 
obvious that a large neighborhood may be well supplied 
with mosquitoes from a single neglected rain-water barrel. 
The Poison of Mosquito Bites. 
That fine old observer, Reaumur, rather thought that a 
poisonous fluid was secreted by the mosquito and that 
its purpose was to cause the blood to flow more readily 
when it bites. Later observers have accepted this state- 
ment, or have denied the existence of such fluid, stating 
that the swelling following the bite was caused by the 
irritation of the puncture, without the aid of poison. 
Dimmock (1881) convinced himself that a poisonous saliva 
was introduced. He noticed that if the mosquito punc- 
tures the skin without entering a blood-vessel, although 
it may insert its proboscis for nearly its full length, no 
poisonous effect is produced upon the skin ; but when the 
proboscis strikes blood and the insect draws its fill, the 
subsequent swelling and poisonous effect are obvious. 
He argued that these effects indicate a constant outpour- 
ing of some sort of poisonous fluid during the blood- 
sucking process. MOSQUITOES IN GENERAL 
45 
The question was finally set at rest by Macloskie (1887), 
who succeeded in demonstrating a poison gland in mos- 
quitoes and in showing that this poison gland is connected 
by a duct with the moutli-parts. This venemo-salivary 
duct is very fine, running backward in the lower part of 
the head in the throat and terminating in the protliorax 
in glands of characteristic structure. The glands are in 
two sets, each set consisting of three glands, two of which 
Fig. 2.—Section of head of Mosquito showing poison gland at p : 
enlarged. (Redrawn from Macloskie.) 
are ordinary salivary glands and the third (between the 
other two) having a different appearance and structure 
and secreting the poison. 
Miall, of England, as late as 1895 stated that it could 
not positively be said whether poison is injected into the 
wound or not. Overlooking1, or not accepting-, Macloskie’s 
demonstration, he says: “ No poison has hitherto been 
demonstrated, and there is some reason to believe that the MOSQUITOES 
46 
irritation of the wound is slight in cold weather and only 
becomes intense during great summer heat.” 
The purpose of the mosquito poison has been a sub- 
ject of some conjecture. The old Reaumur hypothesis, 
that it causes the blood to become more liquid and more 
readily sucked up by the mosquito, has had its adherents. 
Fig. 3.—Salivary glands of Culex at right, Anopheles at left: greatly 
enlarged. (After Christophers.) 
Osten Sacken and Miall, however, believe that it is prob- 
able that the piercing moutli-parts of the mosquito were 
originally acquired for the purpose of sucking the juices 
of plants, and Macloskie advances the idea that the chief 
food of mosquitoes is not animal blood but the proteids of 
plants, and that probably the poison ejected may prevent MOSQUITOES IN GENERAL 
47 
the coagulation of all proteids and so promote the pro- 
cess of suction. 
The amount of irritation caused by the poison of mos- 
quitoes varies greatly with different individuals. Some 
people suffer severely from their bites, while others are not 
at all affected. This is a matter of common observation. 
I have seen a man hunting snipe in a marsh with his face 
protected, but with his neck left exposed. His neck had 
been repeatedly bitten and was so poisoned as to utterly 
destroy its symmetry. At the end of the day he no longer 
possessed a neck, but from his shoulders to his head was 
simply a gradual slope ! 
There can be little doubt that people become inoculated 
against this poison. Persons living in mosquito-ridden 
localities as a rule suffer less than those who come there 
from more favored regions, and it seems likely that after 
a severe case of mosquito-poisoning the inoculating effect 
may last for a long while. An instance of this has been 
sent me by the Rev. Edward Everett Hale, who wrote, 
under date of August 29, 1900: 
“ I think I am an instance of inoculation by mosquitoes’ 
virus. More than fifty years ago I went into the Maine 
woods going to Katalidin. The first afternoon we were 
out hardly an hour, but at night, when we went into 
camp, I counted sixty well defined mosquito bites on my 
right hand alone. Now from that time to this I have 
hardly been troubled by mosquitoes. I dislike their song 
at night, and if I saw one on my hand I should kill it, but 
after the moment of the sting I never remember that I 
have been bitten.” II 
Malaria and Mosquitoes 
THE principal cause of the present widespread inter- 
est in the subject of mosquitoes and mosquito- 
extermination is the perfectly satisfactory proof 
which has been gained during the past few years that 
they are responsible for the transmission of the malarial 
germ from malarial patients to healthy people. The 
causative micro-organism of malaria was discovered by 
the French army surgeon, Laveran, in Algeria in 1880. 
From that time to the present, a small army of workers 
of several different nations have been working upon the 
life history of the malarial parasites, not only of human 
beings but of birds, and our present knowledge is quite 
complete. The idea that mosquitoes might possibly 
spread malaria had been suggested a number of times. 
The most forcible argument, however, was presented by 
Dr. A. F. A. King at Washington, with whom the idea was 
entirely original, in a paper read before the Philosophical 
Society in 1882. The actual demonstration, however, was 
not brought about until much later, and in this actual 
demonstration workers of several nations had a share. 
The researches of MacCallum, of Johns Hopkins Univer- 
sity, while investigating the malarial disease of the coin- 
48 MALARIA AND MOSQUITOES 
49 
moil crow, contributed greatly to the elucidation of a 
knotty point in the life history of the parasite; the stud- 
ies of Boss upon the malarial disease of sparrows in India 
proved effectively the transmission of this disease by 
mosquitoes; while the experimental demonstration of 
the transfer of the parasite of human malaria by mosqui- 
toes was first performed by Italian investigators, al- 
though it has since been done many times in many parts 
of the world by workers of many different nationalities. 
The life history of the malarial parasite of human kind 
maybe briefly summarized as follows: All of the mala- 
rial parasites are protozoans, that is to say animals—and 
not bacteria, that is to say plants. In the human blood 
these protozoa inhabit the red blood corpuscles and in 
the blood they go through a sporulating existence, which 
may continue indefinitely unless checked by quinine or 
in some other way. In the red corpuscle the parasite 
appears as an amoebula which gradually grows until it 
nearly fills the interior of the corpuscle, digesting appar- 
ently the red coloring matter of the blood and forming, as 
the result of this digestion, pigment spots in its interior. 
On reaching full growth the nucleus of the amoebula 
subdivides, each division gathering about itself a certain 
amount of protoplasm, until instead of the single amoe- 
bula the corpuscle contains a large number of spores. 
The walls of the corpuscle then break, and the spores are 
liberated into the blood serum. From a single infection 
this sporulation or liberation of the spores takes place 
practically simultaneously and marks the beginning of 
the malarial spasm. 50 
MOSQUITOES 
The three different kinds of malaria, namely, that in 
which the fever recurs every two days, known as tertian 
malaria, that in which the fever recurs every three days, 
known as quartan malaria, and the severe autumn fever, 
known as sestivo-autumnal fever or tropical malaria—by 
far the most dangerous of the three—are by some writers 
supposed to be caused by distinct species of parasites. 
This view is not held by other writers. But at all events, 
the period of development of the sporulating stage of the 
organism differs in length of time. As is very well 
known, it frequently happens that the malarial fever or 
chill will recur every day. That means, in tertian mala- 
ria, that there has been a reinfection on one of the alter- 
nate days, the development of the amoebulas being con- 
stant in point of time, one set sporulating twenty-four 
hours after the other set. It is just as this sporulation 
occurs—just as the spores are liberated into the blood 
serum—just as the malarial spasm is about to begin, that 
the administration of quinine is most effective. It seems 
to kill the spores when they are liberated, but appears 
to have very slight effect upon the organism when it is 
enclosed in the red blood corpuscle. 
This sporulating development, each of the liberated 
spores attacking and entering new red corpuscles, may 
continue as above stated indefinitely. But not all of the 
amoebulas undergo this development. Some of them, so 
long as they remain in the human body, apparently die 
and are digested by the leucocytes. 
When, however, these forms are taken from the human 
body, even when a blood sample is simply placed under MALARIA ANI) MOSQUITOES 
51 
the microscope for examination, they undergo a develop- 
ment entirely different from the sporulating form. Home 
of them grow large, others put out slender filamentary 
arms, or fiagella, as they are called, which separate from 
the body of the organism and fuse with those which do 
not flagellate. This is the true sexual generation of the 
parasite, the flagellating forms representing the male sex 
and the receptive forms the female sex. The develop- 
ment up to this point will take place anywhere outside of 
the human body—in the stomach of mosquitoes of the 
genus Culex, or, presumably, of other biting insects, but 
it is only in the stomachs of the genus Anopheles, so far 
as observed, that a further development takes place. 
After the fusing of the fiagella with the female germs in 
the stomach of the Anopheles mosquitoes, the fertilized 
organisms attach themselves to the walls of the stomach, 
penetrate the inner walls, and locate themselves just 
under the outer muscular wall. They then rapidly 
increase in size until they eventually become five times 
as large as at first. They are now known as zygotes. 
Clear spaces begin to appear on the surface. These 
clear spaces are known as centromeres, and they are 
rapidly surrounded by minute short dark lines, which, 
when seen under a very high power of the microscope, 
are shown to be spindle-shaped cells, known as blasts. 
These blasts rapidly increase in number until eventually 
they fill the entire zygote, obscuring the centromeres, and 
when this condition of affairs is reached the zygote bursts 
and the blasts are liberated through the muscular wall of 
the stomach into the body cavity of the mosquito. They MOSQUITOES 
52 
are active and penetrate rapidly into the tissue of the 
salivary duct and so into the proboscis of the mosquito, 
and, with the saliva or poison, they enter the blood of the 
next warm-blooded animal which the mosquito bites. It 
is then supposed that the blasts enter the red blood cor- 
puscles and the development re-begins at the stage where 
we took it up. 
It is thus shown that the full development of the mala- 
rial parasite cannot take place within the human body ; 
that the Anopheles mosquitoes are necessary secondary 
hosts ; that the sexual generation of the parasite takes 
place only in mosquitoes of the genus Anopheles ; and 
further, that the old ideas of malaria from bad air (and of 
course the word malaria means bad air), swamp “ miasma,” 
and so on, are to the minds of those familiar with the 
subject of the biology of these low forms of life com- 
pletely overturned. 
Reasoning from the life history of the parasite alone, as 
observed, would not, however, satisfy the minds of people 
at large, and, in fact, it did not satisfy many medical men 
who were not especially familiar with this field of bio- 
logical research. Very many practical . demonstrations 
have therefore been made. One of the most interesting 
was that carried on by Professor Grassi, the Italian, 
during the summer of 1900, in the Plain of Cappacio, near 
Salerno. The objects of this experiment were: (1) To 
afford an absolute proof of the fact that malaria is trans- 
mitted exclusively by the bite of Anopheles mosquitoes ; 
(2) To found, on the results of recent research, a code 
of rules to be adopted for freeing Italy from malaria MALARIA ANT) MOSQUITOES 
53 
in a few years. The experiment consisted in protecting 
from malaria railway employes and their families, living 
in ten cottages, at the stations of St. Nicolo, Yarco, 
and Albanella, situated along the Battipaglia-Reggio 
Fig. 4—Experimental House Occupied by Drs. Sambon and Low on the 
Campagna in the Summer of 1900. (From the Journal of Tropical 
Medicine.) 
Railway. They numbered 104 persons, including’ thirty- 
three children under ten years of age. Of these 104 in- 
dividuals, at least eleven, including four children, had 
never suffered from the disease, not having previously 54 
MOSQUITOES 
lived in a malarious district ; a certain number, it ap- 
peared, had not suffered from it in two or three years, 
and all the others, that is to say, the large majority, had 
suffered from it during the last malarial season, some of 
them even in the winter. During the malarial season, 
the health of the protected individuals was good, with the 
exception of a few cases of bronchitis and a case of acute 
gastro enteritis. None of these cases were treated with 
quinine. The 104 persons, with three exceptions, had re- 
mained free from malaria up to September 16th, the date 
of the report. 
Another very striking experiment which during the 
autumn of 1900 was mentioned in newspapers all over the 
world, was that performed by Doctors Sambon and Low, 
of the London School of Tropical Medicine, in the Ho- 
man Campagna, during the late summer and early autumn 
of 1900. They had constructed a comfortable little five- 
roomed wooden house about three hours’ drive from Ostia, 
in one of the most malarious portions of the Campagna. 
The house was tightly built and was thoroughly screened. 
The experimenters lived in this house through the period 
when malaria is most prevalent. They took no quinine 
and no health precautions beyond the fact that at sun- 
down each day they entered the house and remained there 
until daylight the next morning. Dr llees, of the London 
School, visited them and occupied the house with them 
for a portion of the time, and all three conducted labora- 
tory work in one of the rooms, which was fully equipped 
for such a purpose, and led a busy and contented life. 
They visited the neighboring villages and investigated MALARIA AND MOSQUITOES 
55 
outbreaks of the fever in men and cattle. They received 
and entertained many visitors who were interested in the 
experiment. They turned indoors before six o’clock and 
then stood at the windows and timed the first appearance 
Fig. 5.—The Malaria House on the Campngna, seen from a distance. 
(From the Journal of Tropical Medicine.) 
of Anopheles, which would come at a certain hour each 
evening1 and try to enter the screened windows and doors. 
As Dr. Rees expressed it, “It must have been very tanta- 
lizing for them to be unable to get at ns.” When the 
rains set in, everyone said that that was the critical time 56 
MOSQUITOES 
of the experiment. The people in the surrounding coun- 
try generally became feverish and ill, which meant simply 
that they were all full of malaria, and the chilling caused 
by the rain brought about an explosion of the fever. The 
experimenters, however, went out into the rain and got 
soaked to the skin, but their health remained perfect. 
Not the slightest trace of malaria developed in either of 
them ; as above stated, the spot where the house was built 
was probably the most malarious one in the whole Cam- 
pagna, and it was situated on the banks of one of the 
canals, which was literally swarming with Anopheles 
larvae. The prevalent idea that the night air of the Cam- 
pagna is in itself so dangerous was included in the ex- 
periments and the windows were always left open at 
night, so that if the marsh air had anything to do with 
malaria they would have contracted it. 
A check experiment was carried on at the same time. 
Anopheles mosquitoes which had been fed on the blood 
of a sufferer from malaria in Rome, under the direction 
of the Italian authority Bastianelli, were sent to London 
early in July. A son of Dr. Patrick Manson, the famous 
investigator who first proved the transfer of filaria by 
mosquitoes, offered himself as a subject for experiment, 
and allowed himself to be bitten by the mosquitoes. He 
had never been in a malarious country since he was a 
child, but in due time was taken with a well-marked ma- 
larial infection of the double tertian type, and micro- 
scopical examination showed the presence of numerous 
parasites in his blood. 
No more perfectly practical demonstration is probably MALARIA AND MOSQUITOES 
57 
demanded than is offered by these two experiments, but 
it will be interesting to American readers to give the re- 
sults of some American work. 
Dr. W. N. Berkeley, in the Medical Record of January 
26, 1901, gives a most interesting account of a malarial 
outbreak in a small town near New York City during the 
summer of 1900. Around a large pond in tlie vicinity of 
the town four or five fresh cases had recently developed 
in August. The first case was that of a coachman who 
had caught malaria elsewhere and had relapsed. From 
his quarters in a long row of stables on one side of the 
pond the infection had passed along to other stablemen 
and servants on the same side, to the distance of a quarter 
of a mile from the original site, and a quarter of a mile in 
another direction across the pond one other case appeared 
in a small child. Dr. Berkeley went to the town and dis- 
covered that Anopheles maculipennis was fairly abun- 
dant in every bedroom in that area in which proper search 
was made. The breeding-places seemed to be segregated 
pools at the end of the pond (the pond itself contained 
fish) and post holes and excavations. These last were 
numerous, as many buildings were going up. The fol- 
lowing practical measures were adopted: (1) Extermina- 
tion of all the Anopheles found in houses by a party of 
men sent out for the purpose, and this was followed by a 
systematic introduction of screens in windows and doors; 
(2) Filling in of the smaller breeding-places and the 
drainage of the pond; (3) Tlie seclusion of every mala- 
rious patient by netting and otherwise from the bite of 58 
MOSQUITOES 
mosquitoes, so long as ho had germs in his capillary blood. 
The results were as prompt as they were gratifying. Not 
a single new case of malaria developed ; Anopheles dis- 
appeared entirely from houses where it had been previ- 
ously a night terror, and Culex was greatly diminished 
in numbers. 
The results reached by Dr. Berkeley were admirable, 
and he advises the following official steps for greater 
New York: 
1. Require malarial cases to be reported as scarlet fever 
and diphtheria are now. Malaria is at least as dangerous 
as scarlet fever ; economically it is far more of a scourge, 
for it affects adult breadwinners as well as children. 
2. Send an inspector to every infected house, who shall 
instruct the people to kill all the Anopheles in the house, 
to provide the windows and doors with screens, to isolate 
the patient with particular care from mosquitoes, and to 
cause all the standing water in the vicinity to be drained 
or heavily petrolized. 
Rigid treatment with quinine should be insisted upon 
and the drug furnished gratis to those unable to pay, as 
diphtheria anti toxine is now supplied. Dr. Berkeley 
believes that in a summer or two it would be possible, 
by these measures, to reduce the number of local cases 
by more than ninety per cent. 
Another interesting case lias been reported to me by 
the Rev. Win. Braysliaw, of Chaptico, Md. Cliaptico is 
situated at the head of a wide-spreading bay or elbow of 
the Wicomico River, about eight miles from the point 
where this river enters into the Potomac at Rock Point. MALARIA ANI) MOSQUITOES 
59 
The tide is ordinarily about two feet at the full. The vil- 
lage rests between two hills of 80 or 90 feet elevation. The 
valley is almost flat, and consists of marshy pools, in 
which the mud or ooze can easily be pierced with a strong 
pole to a depth of several feet. Three of these pools or 
ponds are directly in the rear of the house known as the 
rectory, in which he resided with his wife on June 24,1899. 
Neither of them had ever had malaria or fever before, but 
the mosquitoes were so numerous that it was impossible to 
take rest at night for a while. On July lltli his wife was 
taken with malaria, and on September 4th had to be re- 
moved to the mountains. Mr. Brayshaw himself was sick 
most of the time, and every house in the village had from 
one to five persons suffering from malaria. Ho proposed 
ditching and drainage, but there was no money, and every- 
body laughed at the idea, as many of the citizens had 
lived there from childhood to an advanced age. There 
did not seem to be sufficient fall to carry off the “ effete 
matter.” On May 19, 1900, he gained the consent of the 
property owners to ditch through their land a distance of 
560 feet to Chaptico Creek. He paid for this himself. 
The expense was about $40. The result he sums up as 
follows : “ During the summer of 1899, from May to Octo- 
ber, the mosquitoes were so numerous that life was a 
burden during the night, and they were so small that nets 
seemed to have no effect upon them. From May to Octo- 
ber, 1900, quite a number visited us, until June 12th, when 
they disappeared, and we were free from them until the 
last six days in September, when I found a local cause for 
their breeding. In the summer of 1899 every house in the MOSQUITOES 
village had from one to five persons sick with chills and 
fever, and other malarial troubles; doctors in constant at- 
tendance. In the summer of 1900 there were only two spo- 
radic cases of chills, both caused by negligence or in- 
attention to ordinary caution. Everyone in the village 
seems quite free from malaria since July lOtli.” 
In Cuba, as a result of the mosquito-extermination work, 
which will be mentioned in the chapter on “ Yellow Fever 
and Mosquitoes,” Colonel J. R. Keane, U. S. A., Surgeon- 
in-Charge at Havana, wrote me, January 12, 1901, that in 
his opinion there had been a very marked reduction of 
malaria at the military posts in western Cuba. 
The principal arguments in favor of the idea that mal- 
aria may also enter the human system in some other way, 
are that there is malaria where there are no mosquitoes, 
and that there are many mosquitoes in localities where 
there is no malaria. These points are adduced by per- 
sons who, while admitting that it has been proved that 
Anopheles transmits malaria, and that possibly this is the 
only method which has been proved, still insist that there 
may be, and even that there must be, other methods. As 
a matter of fact, it is practically impossible to prove that 
there is local malaria where there are no Anopheles. The 
bite and method of attack of Anopheles is so insidious that 
these mosquitoes attract very little attention where they 
are not especially numerous. One may be bitten by them 
while asleep at night almost without realizing it. Anoph- 
eles may be present where there is no malaria, since it 
will always remain uninfected uuless some vertebrate ani- 
mal suffering with the disease comes to its neighborhood. MALARIA AND MOSQUITOES 
61 
There was no autochthonous case of malarial fever for 
years at the League Island Navy Yard, although there 
was a distinct breeding-ground for Anopheles near by. 
Woldert has caught larvae of Anopheles in a clear pool of 
water in the Pocono Mountains of Pennsylvania, a notable 
health resort, at an elevation of three thousand feet above 
sea-level. The statements that malaria has prevailed when 
there were few or no mosquitoes are always too vague to 
be of value, because it is not definitely stated whether the 
cases were relapses or fresh infections. In cases where 
mosquitoes are numerous, moreover, and there is no mal- 
aria, to the point which we have already made that prob- 
ably no malaria has been brought into the vicinity may 
be added the fact that when mosquitoes are numerous, 
almost without exception they are found to be the com- 
mon species of Culex, which, as shown, have nothing to 
do with malaria. It is often stated, for example, that 
malarial fever is caused by excavating the ground; newly 
turned earth is said to be responsible for it, but, as a 
matter of fact, as pointed out by Ross, there are millions 
of people constantly engaged in digging without suffering 
from the disease more than do others, and then also ex- 
cavations always result in surface pools of water, in which 
for a time Anopheles will frequently be found breeding. 
One curious case has been mentioned by Mr. D. E. Hutch- 
ings, in the English journal, Nature, in which he stated 
that he knew of a medically authenticated case of malaria 
having been caused by fresh earth carried past a window 
in buckets by coolies. This statement is criticized by 
Iioss in the following words : “ Which fact was medically 62 
MOSQUITOES 
authenticated the fact that the patient suffered from ma- 
laria, or that his malaria was caused by the earth carried 
past in buckets ? I can understand the first being certi- 
fied to by a doctor, but scarcely the second. How did the 
doctor prove that the fever was produced by the earth in 
the buckets ? It seems to me that the only way in which 
he could have done so in a trustworthy and scientific 
manner would have been to infect a second person by 
having the buckets carried past a second time. I doubt 
whether such instances—and we see hundreds of them in 
the press—will bear close examination.” 
It has been claimed by Italian observers and others, 
that there is a very exact coincidence between the geo- 
graphic distribution of malaria and Anopheles mosqui- 
toes. Bearing on this point, the conclusions reached by 
Nuttall, Cobbett, and Strangeways-Pigg, in their studies 
in relation to malaria (Journal of Hygiene, vol. i., No. 1, 
January, 1901), are very important. They are as fol- 
lows : 
1. The disappearance of ague from Great Britain does 
not depend upon the extinction of mosquitoes capable of 
harboring the parasites of malaria. 
2. Three species of Anopheles (A. maculipennis, A. 
bifurcatus, A. nigripes) are to be found in Great Britain in 
all districts which were formerly malarious, but also in 
places concerning which there is no record of the former 
prevalence of ague. 
3. The Anopheles to-day are most numerous in low- 
lying land containing many ditches, ponds, and slowly 
flowing water, suitable for their habitat, and correspond- MALARIA AND MOSQUITOES 
03 
ing to the districts where ague was formerly preva- 
lent. 
4. Since the disappearance of ague does not depend 
upon the extinction of Anopheles, it is probably due to 
several causes operating together : 
(a.) A reduction in the number of these insects conse- 
quent upon drainage of the land, this being in accord 
with all the older authors, who attributed the disappear- 
ance of ague largely to this cause. 
(b.) Reduction of the population in infected districts as 
the result of emigration, about the time when ague disap- 
peared from England. This would naturally reduce the 
number of infected individuals, and thus lessen the 
chance of the Anopheles becoming infected. 
(c.) It is possible that the use of quinine has reduced 
the chances of infecting the Anopheles, through checking 
the development of the parasites in the blood of subjects 
affected with ague. 
Of these, the first-mentioned cause seems to have been 
chiefly operative. The possibility is not yet excluded of 
there being another intermediary host besides man, capa- 
ble of harboring the parasite, and, assuming that this 
were so, this host may have become extinct in the low- 
lands where it is known that the fauna and flora have al- 
tered. 
5. The coincidence of the geographical distribution of 
ague and Anopheles as claimed by Grassi for Italy, and 
as probably holding good for other parts of the world, is 
hereby disproved for England, and consequently the gen- 
eralizations are proved to be premature whereby he ex- 64 
MOSQUITOES 
eludes other blood-sucking insects from being possible 
hosts of malarial parasites on the strength of his sup- 
posed geographical agreement. 
6. Since the geographical distribution of Anopheles in 
England is wider than the former distribution of ague in 
that country, we are forced to conclude that it is not a 
matter of the geographical distribution of Anopheles as 
much as of their numerical distribution. 
7. Our observations having proved the existence of 
Anopheles in lion-malarious districts, we believe that they 
will explain the occasional occurrence of ague in out of 
the way places, without making it necessary to assume 
that malaria-bearing mosquitoes have been freshly im- 
ported, for, given suitable conditions of temperature and 
the requisite number of Anopheles, a malarious subject 
coming from other parts might well infect the local in- 
sects, which in turn would spread the infection to healthy 
persons. 
8 We would suggest to those engaged in the investi- 
gation of malaria in other countries, that they search as 
carefully for Anopheles in lion-malarious as in malarious 
regions. More data as to the number of these insects in 
various localities are certainly required, though we are 
fully aware that numerical estimates permit of a consider- 
able degree of error. Nevertheless, they would always 
possess a relative value. 
Grassi lias repeatedly asserted that the geographic dis- 
tribution of Anopheles in Italy coincides with that of 
malaria, and on the strength of their wider geographic 
distribution he excludes a number of blood-sucking creat- MALARIA AND MOSQUITOES 
65 
ures, such as mites, ticks, stable-tiies, gad-tlies, black- 
flies, punkie-flies, lice, bedbugs, and Culex, from being 
possible carriers of malaria. 
Probably nothing more need be said in regard to the 
general subject of malaria and mosquitoes. The case is 
abundantly proven, and it remains necessary from the 
health standpoint to know all about the mosquitoes of the 
genus Anopheles—how and where they live and breed, 
and how to distinguish them from other mosquitoes in all 
stages of their existence. All these facts will be con- 
sidered in Chapter IV. Ill 
The Common Mosquitoes of the Genus Culex 
CULEX is an old genus named by Linnaeus in 1735, 
which for a long time comprised all the mosqui- 
toes. But other genera have been erected, and now 
the mosquitoes are included in a family known as the Cu- 
licidae, which comprises several genera and very many 
species. Culex, however, is the typical genus, and in- 
cludes the commoner, most abundant, and most wide- 
spread kinds of mosquitoes. We have at least twelve 
species in the United States, and probably more than 
two hundred species exist in different parts of the world. 
The genus lias no geographic limitation, and its species 
are found in the Arctic regions as well as in the tropics. 
Not only has the genus itself apparently no territorial re- 
strictions, but the individual species are many of them 
widespread. There are a half dozen or more which may 
be found practically everywhere in the United States. 
There are others which extend from Cuba to Alaska. A 
few others are more restricted. The life history of the 
common European Culex, known as Culex pipiens, was 
studied and described very accurately as long ago as 1691, 
by Bonanni, in his “ Micrographia Curiosa,” published at 
Borne that year, and I am not sure that mosquito biology 
60 THE COMMON MOSQUITO 
67 
was not well known at an even earlier date. The French 
observer, Reaumur, studied the same species more than 
150 years ago, near Paris, and his account of the devel- 
opment of Culex has remained standard from that time 
almost to the present day. The full life history of no 
American species of Culex, however, was published until 
1896, when the life history of Culex pungens Wiedemann 
was worked out by the writer at Washington and pub- 
lished in Bulletin 4, n. s., of the Division of Entomology, 
of the United States Department of Agriculture. 
Fig. 6.—Egg Mass of Culex pungens ; enlarged; with individual eggs, 
still more enlarged, at left. (Author’s illustration.) 
Culex pungens is one of our common North American 
species. It abounds everywhere, from the White Moun- 
tains of New Hampshire down into Central America, and 
is, perhaps, the most abundant of our mosquitoes. It 
breeds exclusively in fresh water, and its larvae may 
everywhere be found in water buckets and barrels, in 
transient pools of rain-water, in fresli-water swamps, along 
the borders of inland lakes and ponds, and, in fact, in all 
of the out of the way places which have been mentioned 
in Chapter I. Its life history may be taken as typical of 
the genus Culex, all other species probably closely re- 68 
MOSQUITOES 
sembling this form in all of their early stages and in 
their periods of development. 
The female lays lier eggs upon the surface of the water, 
balancing herself upon some floating object during the 
operation, and extruding them in an irregular, raft-shaped 
mass, which is usually shaped something like a pointed 
ellipse somewhat convex below and concave above, all of 
the eggs standing on end and closely applied, side by 
side, in from six to thirteen longitudinal rows, with from 
three or four to forty eggs in a row. The number of eggs 
in each batch varies from 200 to 400. As seen from above, 
the egg mass is gray-brown, from below, silvery-white, 
the latter appearance being due to a film of air which 
protects them from the water. It seems impossible to 
wet these egg masses. They may be pushed under the 
water, but bob up apparently as dry as ever. As the 
eggs are very small, being only 0.7 mm. long, and 0.16 
mm. in diameter at the base, the entire egg mass is not a 
large object, seldom, in fact, reaching a length of more 
than a quarter of an inch. The mass separates rather 
regularly and the eggs are not stuck together very firmly. 
After they have hatched, the mass will disintegrate in a 
few days, even in perfectly still water. The individual 
eggs are slender, broader and blunt at the bottom, and 
somewhat pointed at the tip. The tip is always dark 
grayisli-brown in color, while the rest of the egg is dirty 
white. Sixteen or more hours after laying, the eggs 
hatch, generally about noon on warm days, but some- 
times they will remain unhatched for two days or even 
longer, especially in cold weather. THE COMMON MOSQUITO 
69 
The larvae issue from the under side of the egg masses 
and are extremely active at birth, wriggling rapidly in 
the water about the eggs. They are very minute and 
move so rapidly that it is difficult to form any impression 
of their shape and structure except when they are at rest. 
Fig. 7.—Young Larvae of Culex pungens ; enlarged. (Author’s illus- 
tration.) 
They come frequently to the surface to breathe, and dur- 
ing the first few hours many of them remain under the 
egg mass, where they get air from the air film by which 
the egg mass is surrounded. One of the first peculiarities 
which strikes one on observing these newly hatched 
larvae or wrigglers under the lens is that the mouth is 
furnished with tufts of filaments which are constantly in 
vibration. The head is large, the antenna; long, the thorax 
somewhat swollen, and the abdomen slender. The sides 
of the body are furnished with stiff bristles. From the 
next to the last segment of the abdomen there protrudes 70 
MOSQUITOES 
a long tube nearly as thick as the body itself, and it is 
this tube which is extruded from the surface of the water 
every time the larva rises to breathe. The object of this 
extrusion is to get air, and this tube is the breathing tube 
of the insect. Its extremity is furnished with a breathing 
Fig. 8.—Moutli-parts of Larva of Gulex pungens ; greatly enlarged. 
(Author’s illustration.) 
hole, or spiracle, and into it run two main trachea, or 
breathing- tubes, which extend through the body of the 
insect, giving off branches here and there, and thus carry- 
ing air to all of its tissues. The true end of the body is 
furnished with four flat flaps, the exact purpose of which THE COMMON MOSQUITO 
71 
is not known, but which may possibly function as gills 
while the larvae are very young, and are certainly of use as 
swimming organs. When 
the breathing tube is at the 
surface of the water the 
body of the wriggler ex- 
tends down below the sur- 
face at more or less of an 
angle with the water sur- 
face, and its mouth-parts, 
as just stated, are constant- 
ly in vibration, bringing 
into its mouth any minute 
particles which float in sus- 
pension in the water. Oc- 
casionally it descends to 
the bottom, jerking its body 
violently from one side to 
the other. The flaps at the 
end of the body undoubt- 
edly assist in this motion. 
The jerking motions are 
not so evident when the 
larva or wriggler is de- 
scending as when it be- 
comes necessary for it to 
ascend once more; in other 
words, its specific gravity 
seems to be greater than that of the water and sometimes 
it can be seen to descend without effort, simply sinking 
Fig. 9.—Full-grown Larva of Culex 
pungens ; enlarged. (Author’s il- 
lustration.) 72 
MOSQUITOES 
down. After one of them lias wriggled up to the surface 
of the water, its breathing tube extrudes, fresh air runs 
into its tracheae, and the tension of the so-called surface 
film of the water assists it 
in maintaining its position. 
After an introductory wrig- 
gle, which pulls the breath- 
ing tube below, the insect 
sinks. The larval Culex ap- 
pears to pass through three 
different stages of growth, 
reaches maturity, and trans- 
forms to pupa, in a minimum 
of about seven days in warm 
summer weather. 
The pupa differs markedly 
from the larva in the great 
swelling of the thoracic seg- 
ments, as shown in the ac- 
companying cut. The pupa 
seems to be all head and 
thorax, with a slender abdo- 
men and with two large flaps 
at the end of the abdomen, 
which assist it in swimming 
whenever it feels that it has 
to swim. In this stage the 
insect is lighter than water. 
It remains motionless at the 
surface and when disturbed 
Fig. 10.—Pupa of Ctdex pun- 
gens; enlarged, with Anal Seg- 
ment below, still more enlarged. 
(Author’s illustration.) THE COMMON MOSQUITO 
73 
does not sink without effort, as does the larva, but is 
only able to descend by violent muscular action. It 
wriggles and swims as actively as does the larva and 
soon reaches the bottom of the water. As soon as it 
ceases to exert itself, however, it floats gradually up 
to the surface once more. As pointed out in our con- 
sideration of the habits of mosquitoes in general, this 
activity on the part of the pupa is necessary to preserve 
it from fishes and from its natural enemies. It is very 
active and difficult to capture. The mortality of the 
pupae, however, is not great, except through the efforts 
of fish and its other enemies, while that of the wrigglers 
or larvae is apt to be great through drowning. When- 
ever a larva becomes sick or weak, or for any reason un- 
able to exert sufficient muscular force to wriggle to the 
surface at frequent intervals, it drowns. It seems almost 
like a contradiction in terms to speak of an aquatic insect 
as drowning, but this is a frequent cause of mortality 
among mosquitoes. This fact also explains the efficacy 
of the remedial treatment which causes the surface of the 
water to become covered with a film of oil of any kind. 
Aside from the actual insecticidal effect of the oil, the 
larvae drown from not being able to reach the air. Or 
they may draw drops of oil into the tracheae, clogging 
them and preventing the passage of the air. The struct- 
ure of the larvae and pupae at the different stages is so 
well shown in the accompanying figures as to render it 
unnecessary to describe them fully. One peculiar struct- 
ure of the pupa, however, has already been pointed out 
in the general consideration of mosquitoes, and that is the 74 
MOSQUITOES 
trumpet-shaped breathing organs, which now issue from 
the thorax and no longer from the abdomen as with the 
larva. In Gulex pungens, these ear-shaped, trumpet-like 
Fig. 11.—Adult male of Cnlex pungens; with parts enlarged. (Author’s 
illustration.) 
breathing organs are rather slender and of the propor- 
tions indicated in the figure. 
The duration of the pupal stage in midsummer with 
this species at Washington is about two days. A mini- 
mum generation, therefore, of Gulex pungens will occupy 
ten days, as follows : sixteen to twenty-four hours for the 
egg ; seven days for the larva, and two days for the pupa. THE COMMON MOSQUITO 
75 
In my observations on this species I was interested to 
notice that on the first day the adults which emerged 
from the pupae were invariably males; on the second day 
Fig. 12.—Adult female of Gulex pungens; enlarged. (Original.) 
the great majority were males, but there were also a few 
females; the preponderance of males continued to hold for 
three days ; later the females were in the majority. 
The duration of a generation as indicated above, is, as 
we have seen, a minimum duration. If a spell of cold 
weather should come in the middle of the summer, the 76 
MOSQUITOES 
life of the wrigglers may be almost indefinitely pro- 
longed. I have watched them for twenty days, during 
which time they did not reach full growdli. The short- 
ness of the minimum generation, however, is very signifi - 
cant and accounts for the fact that swarms of mosquitoes 
develop upon occasion in surface pools of rain-water, 
which may dry up entirely in the course of two weeks or 
less, or in a chance bucket of water left undisturbed for 
that length of time. 
Dr. John B. Smith has reared the species, as elsewhere 
stated, from larvae found in January frozen in ice. In 
studying the larvae after they had been thawed out he 
found that they remained under the water for a long 
time, certainly fifteen minutes, and probably much 
longer. These observations thus differ radically from 
those which I made in summer, and show that these larvae 
must be studied still more before we know all that may 
be found out about them. 
This species, Culex pungens, is said by Dr. H. A. Yea- 
zie, of New Orleans, to breed most extensively in the 
gutters in that city. They are found in gutters in which 
the water runs slowly, but more plentifully in those where 
there is no current. In gutters that receive the refuse of 
the gas works, tar factories, soap works, and oil establish- 
ments, there are no larvae. They live in gutters contain- 
ing Mississippi River water, but do not prosper. Dr. 
Yeazie thinks the fine sediment in the Mississippi water 
blocks their breathing tubes, since they flourish well in 
this water after it has been filtered. 
Reverting once more to tlie distribution of the different THE COMMON MOSQUITO 
77 
species of Culex, I have been able to determine, by exam- 
ination of the locality labels in the collection of the United 
States National Museum, that in almost every locality in 
the United States there may be found five or six species 
of this genus. The commoner forms are Culex conso- 
brinus, C. stimulans, C. per turbans, C. pungens, and C. im- 
piger, and these forms are found almost all over the 
country, from New England to Texas, and even to 
southern California. C. consobrinus is perhaps a more 
northern form than the others, and is one of the species 
which occurs in Alaska. It is also found in the White 
Mountains in New Hampshire and in the Catskill Moun- 
tains in New York, and occurs on the Saskatchewan Biver 
in British America, and in Minnesota and North Dakota. 
We have in this country no species of the genus Culex 
which inhabits really salt water and, in fact, no species of 
mosquito can definitely be said to occur in water as salt 
as the ocean. Three or four Australian species are said 
to live in salt water, but, so far as I have been able to 
learn, there is not sufficient substantiality in this record. 
Culex salinus of Europe is also said to breed in salt 
water. We have in the United States, however, a species 
of Culex which occurs in brackish water, that is to say, it 
is able to breed in, and prefers apparently to breed in, 
the brackish swamps which are occasionally overflowed 
at very high tides, though not affected by the daily 
high tide. This is Culex sollicitans (see Eig. 1), a small 
gray mosquito which has its legs banded with black and 
white. It is ordinarily known as the ring-legged mos- 
quito and is the most common form on the Atlantic sea- 78 
MOSQUITOES 
coast. It occurs along the New Jersey coast, the Long 
Island coast, along Staten Island, at Virginia summer 
resorts, and at Tybee Island, Ga., and St. Augustine 
and Charlotte Harbor, Fla. Curiously enough, Dr. A. D. 
Hopkins states that what is probably this same species 
apparently breeds in West Virginia in pools and small 
streams fed from coal-mine drainage, the water of which 
contains a large percentage of sulphate of iron. 
There is no doubt that this Culex breeds in great num- 
bers in the pools left by the highest tides, which subse- 
quently become freshened to some extent by rains or by 
the entrance of spring water. It has been caught, how- 
ever, considerable distances inland, and the question 
arises, has it been carried to such spots by trains only, 
or will it breed after being so carried for at least one or 
two generations in fresh water ? Mr. Benjamin S. Pas- 
cliall, of Newfield, N. J., caught this species in August, 
1900, in his garden. They could be found anywhere in 
the long grass, practically by the thousands. Newfield 
has one of the highest altitudes in South Jersey, being 
about 130 feet above the tide and over thirty miles from 
the sea. In Mr. Pascliall’s opinion, the species must 
breed there. There had been no wind for a long time 
before their appearance and the microscope showed all 
specimens to be freshly hatched. On September 4tli, he 
tried an experiment and placed a pail of water in a spot 
where these insects were thickest. By the end of a week 
he had procured many eggs, and September 14th he 
succeeded in hatching out several hundred mosquitoes, 
but not one single specimen of sollicitans; all were pun- THE COMMON MOSQUITO 
79 
gens. He concludes that Culex sollicitans appears in 
the perfect state throughout South Jersey, being found 
from May to October, but is not always common. Mr. 
La Rue Holmes, of Summit, N. J., has several times 
sent me specimens of sollicitans taken at Summit, which 
is about twelve or fifteen miles from the nearest salt 
marsh. I am inclined to think that although this species 
may be found widespread through the summer in various 
parts of New Jersey, this abundance is due to its car- 
riage in numbers from the sea-coast by railway trains, 
and even if it does breed for a generation or two in 
fresh water, the supply is constantly renewed from the 
sea-shore. 
Culex impiger is another of the more northern mos- 
quitoes, having- been collected by Mr. Trevor Kincaid on 
the Harriman Alaskan Expedition, and having- been given 
me by Dr. Walter Evans, of the United States Department 
of Agriculture, who has investigated the agricultural re- 
sources of Alaska. Mr. F. C. Pratt has found it breeding 
in privy vaults in Alexandria, Va., and this species is 
likely to be the one found usually in such places, where 
the water is fouled with decomposing or excreted animal 
matter. 
The distribution of our commoner species of Culex, so 
far as known to the writer, is as follows: 
CuiiEX consobrinus Desv. 
Habitat: White Mountains, N.H. ; Beverley, Mass., Septem- 
ber 28 (Nat. Mus.) ; Catskill Mountains, Greene County, 
N.Y., 2,500 feet (Howard); Illinois, March 21, April 29, 
May 6, October 16 (Nason); St. Anthony Park, Minn., April, 80 
MOSQUITOES 
May, on snow (Lugger) ; Saskatchewan River, British 
America; South Dakota (Nat. Mus.); Lincoln, Neb. 
May, September (Bruner) ; Colorado (Nat. Mus.) ; Hot 
Springs, Ark. (Curry); Los Angeles, Cal., February (Co- 
quillett) ; Argus Mountains, Cal., April (Nat. Mus.) ; Santa 
F6, N. Mex., July (Cockerell) ; New Orleans, La., Novem- 
ber (Thayer); Ottawa, Canada, May (Howard) ; Summit, 
N. J. (Holmes) ; Trenton, Ontario, May 24 (Fletcher) ; Flat 
River, Mo., November (Pergande). 
CULEX ANNULATUS Meig. 
Habitat: New Bedford, Mass. (Johnson) ; Lincoln, Neb., 
May (Bruner) ; Santa Fe, N. Mex., July (Cockerell) ; Stan- 
ford, Cal. (Kellogg); Laggan, British Columbia (Wick- 
ham). 
Culex IMPIGER Walk. 
Habitat: White Mountains, N.H. ; Beverley, Mass., May 24, 
June 2 (Nat. Mus.); Ithaca, N.Y., July 9 and 17, August 
28 ; Wilmutli, N.Y., June 10 (Comstock) ; Saskatchewan 
River, British America (Nat. Mus.) ; Minnesota (Lugger) ; 
Loudoun County, Va., August 26 (Pratt) ; Tyrone, Ky., 
July 14 (Garinan); Georgia (Nat. Mus.) ; Mesilla, N. Mex. 
(Cockerell); Isle of Pines, West Indies (Scudder) ; Port- 
land, Jamaica (Johnson) ; District of Columbia, September 
12 (Barber); Alexandria, Va. (Pratt) ; Ogdensburg, N.Y., 
June 3 (Howard) ; Buffalo, N.Y. (Wright) ; Middletown, 
Conn., June (Davis) ; Ottawa, Canada, May 31 (Howard); 
Chats Rapids, Quebec, May 24 (Fletcher) ; Buckeye, Wash. 
(Nat. Mus.) ; Stikine River, British Columbia (Wickham); 
City of Mexico (Herrera). 
CULEX PERTURBANS Walk. 
Habitat: Lakeland, Md., August 8 (Pratt) ; Virginia, August 
17 (Pergande) ; Tick Island, Fla., May 12 (Johnson); THE COMMON MOSQUITO 
81 
Texas (Nat. Mus.); Bayamon, Porto Rico, January (Busck); 
District of Columbia, September 1-5 (Barber) ; St. Elmo, 
Va., June, July, Virginia Beach, August (Pratt); Mel- 
bourne, Fla. (Peek); Cuba (Lazear, Read). 
Culex PUNGEXS Wied. 
Habitat: Ottawa, Canada (Fletcher) ; White Mountains, 
N. H. ; Beverley, Mass., September 5 ; Cambridge, Mass., 
September 10 to November 5 ; Boston, Mass. ; Baltimore, 
Md., November 5 (Nat. Mus.), November 26 (Lugger); 
Charlton Heights, December 1 (Pratt); District of Colum- 
bia, January 30, March 5, May 6 and 15, June 28, July 11, 
August, October 10, 15, 25 and 31, November 4, 8, 13, 16 
and 23, December 23 (Pergande) ; Ithaca, N. Y., May 29, 
July 17, August 28 (Comstock) ; Illinois (Nason) ; Minne- 
sota (Lugger) ; Lincoln, Neb., September 20 (Bruner) ; 
Lexington, Ky., November 10 ((Jarman) ; New Orleans, 
La., December 17 (Howard); San Antonio, Tex., May 5 
(Marlatt) ; Hot Springs, Ark. (Curry) ; Georgia, August 
(Coquillett) ; Melbourne, Fla. (Peek) ; Portland, Jamaica 
(Johnson) ; Mexico City (Barrett) ; District of Columbia, 
August 22, 28, September 1 (Barber) ; Jackson, Va., October 
(Thayer) ; Woodstock, Va., June (Pratt) ; Newport News, 
Va., October (Thayer); Stillwater, Okla., June (Bogue); 
Philadelphia, Pa. (Woldert) ; New Orleans, La., June 
(Veazie) ; Eastern Texas (Woldert) ; Summit, N. J., May 
(La Rue Holmes) ; Newfiekl, N. J. (Paschall) ; Middletown, 
Conn., June (Davis); Cuba (Lazear, Reed); Agric. College, 
Miss. (Herrick) ; Flat River, Mo., November (Pergande), 
Bluefields, Nicaragua (Wailes); Guanajuata, Mex. (Duges). 
Culex stimulans Walk. 
Habitat: White Mountains, N. H. ; Beverley, Mass., June 2, 
July 9 ; Cambridge, Mass., May ; Jamaica Plain, Mass., 82 
MOSQUITOES 
August 25 (Nat. Mus.); Siasconsett, Mass. (Wilder) ; Bal- 
timore, Md. (Lugger) ; Illinois, August 1, September 15, 
October 5 (Nason) ; Agricultural College, Mich. (Gillette) ; 
Saskatchewan River, British America (Nat. Mus.) ; Lin- 
coln, Neb. (Bruner) ; Colorado (Nat. Mus.) ; Ithaca, N. 
Y., June 13, 18, 29, July 14, August 28 ; Wilmuth, N. Y., 
June 10 (Comstock) ; Rochester, N. Y. (Ewers) ; Buffalo, 
N. Y. (Wright) ; Brooklyn, N. Y. (Van Matie) ; Georgia 
(Nat. Mus.); Bladensburg, Md., May 27 (Barber); St. 
Elmo, Va., June 5 (Pratt) ; District of Columbia, Septem- 
ber (Barber) ; June 10 (Miss L. Sullivan) ; Ottawa, Canada, 
June 1 (Howard); Ogdensburg, N. Y., June 3 (Howard) ; 
Rochester, N. Y., June (Ewers) ; Summit, N. J., May (La 
Rue Holmes); Middletown, Conn., June (Davis); Lake 
Maxinkuckee, Iiul. (Evermann) ; Mesilla, N. Mex., Octo- 
ber 20 (Cockerell) ; Tacna, Ariz., April 13 (Hubbard); Jua- 
rez, Mexico, May 12 (Cockerell) ; Summit, N. J. (Holmes); 
Flat River, Mo., November 1 (Pergande). 
CULEX SOLLICITANS Walk. 
Habitat : Maine, August ; Beverley, Mass., June, September 
15 (Nat. Mus.) ; Siasconsett, Mass. (Wilder) ; Avalon, An- 
glesea, and Atlantic City, N. J., July 10 to 29 (Johnson) ; 
Summit, N. J., September (Holmes) ; Far Rockaway, Long 
Island, N. Y., August 30 (Howard) ; District of Columbia 
(Pergande) ; Georgia (Nat. Mus.) ; St. Augustine and Char- 
lotte Harbor, Fla., July; Portland, Jamaica (Johnson); 
Chesapeake Beach, Md. (Barber) ; Baltimore, Md. (Thayer); 
Plymouth, N. C. (Thayer). 
CULEX TARSALIS Coq. 
Habitat : Argus Mountain, Cal., April ; Folsom, Cal., July 
3 (Nat. Mus., Koebele); Stanford, Cal. (Kellogg) ; Corval- 
lis, Oregon (McElfresh). THE COMMON MOSQUITO 
83 
CULKX TRISERIATUS Say. 
Habitat : White Mountains, N. H. (Nat. Mus.); Delaware 
County, Pa., June 12 (Johnson) ; Washington, D. C., May 
5 and June 10 ; Loudon County, Va. (Pratt) ; Near Balti- 
more, Md. (Thayer); Roanoke, Va., October (Thayer) ; 
Middletown, Conn., June (Davis) ; New Jersey (Woldert). 
Dr. J. B. Smith’s Observations on Culex pungens. 
The observations made by the well-known State ento- 
mologist of New Jersey on the larvae hibernation of Culex 
pangens in pitcher plants are of such great interest that 
they are given in full from advance sheets of an article 
which Dr. Smith has been good enough to send me and 
which was prepared for the Entomological News. 
New Jersey’s reputation for mosquitoes is well established, and 
more people come into our State annually to be bitten by our 
shore species than go to any other State in the Union for any 
like purpose. In some of the swampy districts in the Pines they 
make life a burden at times, so when my good friend, J. Turner 
Brakeley, wrote me in the late summer that in looking at the 
contents of some pitcher-plant leaves he had found mosquito 
larvae in abundance in the water they contained, it made no 
especial impression upon me. It was in a way what I would 
have expected, though no one had noted this so far as I could 
then remember. Dr. Riley at one time bred a number of species 
from this plant; but seems either to have found no mosquitoes 
or to have ignored them. Mrs. Treat made many interesting 
observations on the feeding habits of the plant itself, feeding the 
leaves with raw meat in place of the insects that ordinarily fall 
into them : but she also ignored the mosquitoes. 84 
MOSQUITOES 
Late in November (1900), I spent three days with Mr. Brakeley 
at Lahaway and one of our walks was into a huckleberry and 
wild cranberry swamp, where pitcher plants were abundant. 
Though the weather was yet mild, mosquitoes were no longer 
obtrusive. There were occasional specimens, to be sure, but they 
seemed to be left-overs not yet in hibernating quarters. The 
interesting point was that in every leaf examined there were 
wrigglers, varying in size from an eighth to a quarter of an inch 
in length. There was always a mass of insect fragments at the 
bottom, say from one half to an inch in depth, and in composi- 
tion this varied from a dense black ooze at the lowest point to 
entirely or only partly decayed specimens at the top of the mass. 
The question arose at once whether these larvae would yet 
develop that season, and from published accounts I assumed 
that they must, or perish. l)r. Howard, in his careful account 
of the species of Culex, and especially C. panyens, says nothing of 
larval hibernation. He records finding adults and, indeed, this 
was in accordance with my own experience. 
The matter dropped here until late in January when, during a 
bitter cold spell, Mr. Brakeley cut out a few pitcher leaves, 
stripped them from the core of solid ice they contained, and 
looking through it saw wrigglers imbedded in all parts of it, in 
all sorts of shapes; but mostly in a half coil. The temperature 
of the bog had been down to 2° below zero, as registered by a 
standard minimum thermometer, and radiation probably lowered 
this even more. 
A number of leaves were gathered, the cores of ice with all they 
contained were removed, and the lumps were placed together in 
a jar in a moderately warm room. The ice melted slowly, and 
as the larva? were gradually freed, they dropped to the bottom, 
where for a time they rested, apparently lifeless. But as the 
amount of ice decreased, feeble motions here and there indicated 
a revival, and long before the lumps were completely melted, THE COMMON MOSQUITO 
85 
those first released were moving about actively. This, be it 
noted, was in water not much above the freezing point. Soon 
after the ice had melted and the debris had settled, the insects 
were busily engaged in apparent feeding. 
The specimens were sent to me as a curiosity, January 22d, and 
arrived in very good condition. A few had succumbed to the 
dangers of the journey, but altogether there was a good lot 
of lively wrigglers. The bottle was nearly full of water, it had 
had a five mile wagon drive over a rough road, had been trans- 
shipped no less than four times before it reached New Brunswick 
and was thrown into the delivery wagon. Under these circum- 
stances any regular breathing of the kind usually described was 
utterly out of the question, and drownings should have been 
numerous ; but really only a very small number of specimens 
died. 
At short intervals other jars were received, all of melted ice 
taken from pitcher plants, until I had several hundred active 
wrigglers in eight different jars. Some of the leaf chunks, Mr. 
Brakeley informs me, had only a very few larvae—ten or a dozen; 
others ran as high as thirty or more. 
The jars were all placed on a counter shelf near a steam radia- 
tor and it was expected that in a few days there would be pupae 
and adults. But the days passed into weeks and the weeks into 
months, without change other than a gradual—a very gradual, 
increase in size. The larvae were just as active and lively as they 
could be expected to be, and were feeding continuously; but 
evidently something was lacking. Besides, they did not in all 
respects behave as, according to Dr. Howard’s account, they 
should have done. I do not suggest that the account as printed 
is not a perfectly accurate record of facts: merely that my speci- 
mens were Jersey mosquitoes and therefore a law unto them- 
selves. 
As the fragments settled to the bottom, the water became 8G 
MOSQUITOES 
almost entirely clear and larvae congregated over this sediment, 
feeding head down and frequently rooting into it; varying the 
process by working along the glass of the jar on the side away 
from the light. It was very rare that an individual was 
observed at the surface with the spiracle in breathing position. 
I Avatched patiently several times, for fifteen minutes at a time, 
without noting a single individual rising to the top. Mr. Dick- 
erson, one of the students, watched more or less continuously 
for tAVo hours on one day and declares positively that during 
that period only a small percentage of the entire number came 
to the top. On two or three occasions where my work was such 
as to alloAv it, I kept a jar within sight the entire day, and I 
have no hesitation in saying that some individuals remained 
below the surface for hours. 
Occasionally a number of specimens would be at the surface, 
feeding, head up, so that the mouth-brushes skimmed the sur- 
face, and these were watched on occasions for fully twenty 
minutes without noting any attempt to assume the breathing 
position. In fact, during the two months that these larvae were 
under daily observation, the rising to the surface to breathe was 
the rare exception rather than the rule. 
As to feeding positions, all of those figured by Dr. Howard 
Avere noted. Usually they were head down, over the bottom 
sediment, or head up, feeding along the sides of the glass or at 
the top. The mouth-brushes serve as organs of locomotion as 
well as for feeding, and the insects are perfectly able to make 
their way from place to place without moving any other part of 
the body. 
The jerky, wriggling motion is used when they wish to get 
away quickly, and as often to get down to the bottom as to get 
up to the surface. They can, and often do, sink slowly to the 
bottom without any motion whatever, and often, to sink more 
rapidly, they curl themselves up into a ring. Occasionally a speci- THE COMMON MOSQUITO 
87 
men will get hold of a bubble of gas forming at the bottom, and 
will allow itself to be floated to the surface. It is immensely inter- 
esting to watch these little creatures ; but as week after week 
went by without change it became just a little tedious. To has- 
ten matters a little, on March 1st I placed the two jars first re- 
ceived on a water bath, which was kept at a temperature as nearly 
constant as the varying gas pressure allowed. Ordinarily the 
thermometer ranged between 100° and 110°, but it has gotten as 
high as 120° and as low as 90°. These were exceptions, however, 
and not exceeding the ordinary out-door range in June. The 
temperature of the water in the jars ranged between 80° and 90° 
almost uniformly. 
A difference in the rate of growth was observable after a few 
days, and several specimens seemed approaching the adult con- 
dition ; finally, on March 18th, I noticed the first pupa, seven- 
teen days after placing the jar on the water bath. From this 
the adult emerged March 21st and proved to be a female Culex 
pungens. Three other pupae were formed within a week after the 
first, and a second adult, also a female, was obtained March 24th. 
As to the habits of the larv;e in the two jars artificially forced 
there was little to note as different from those in the normal 
laboratory temperature, which varied from 40° to 78°, averaging 
a little under 70° for the twenty-four hours. They fed in much 
the same manner, kept away from the light as much as possible, 
passed most of their time at the bottom, but were more lively 
and more frequently at the surface. The jars were kept covered 
except for a few minutes each day and in none of them did the 
water foul, despite the vegetable and animal matter present in 
each. 
On March 24th I made an experiment that resulted fatally. It 
occurred to me that possibly the slow growth was due to lack of 
food, and Mr. Brakeley had written me that the wrigglers at- 
tacked and devoured a small gnat which was breeding in his jars, 88 
MOSQUITOES 
suggesting that possibly a mutton chop might help matters 
along. 
On March 24th, I put a small lump of raw beef chopped fine, 
into each of five experiment jars. The next day I could give only 
a casual glance before going out of town, and this showed noth- 
ing unusual; but the day after, March 26th, when I reached the 
laboratory at 8 a.m. I saw at once that something was wrong, be- 
cause all the living larva; were at the surface, head down, spira- 
cles reaching the air. In every jar into which I had placed the 
meat I noted the same appearance, and I hastily fished out every 
particle. But it was too late : more than half were already dead, 
others seemed to show fungoid growth proceeding from the seg- 
ments, so, to prevent their dying, I killed them off with a dose of 
formalin. One large jar received in February was left unharmed, 
and this was placed on the water-bath March 26th. Nothing has 
come from it at the date of present writing, and nothing may ever 
come from it, but its history must be written later. 
But this experiment, fatal as it proved, was of some value. It 
shows that water too foul with animal decay is not suitable for 
mosquito larvae.* Vegetable decay and the harder refuse from 
insect bodies will help along the development; but beyond that 
the water must be clean. It seems to indicate further that the 
condition of the water may very largely determine the frequency 
with which the supply of oxygen must be renewed from above the 
surface. In June, with a supply of water at a relatively high 
temperature in which microscopic life is swarming, I have no 
doubt Dr. Howard’s observations would be exactly duplicated. 
With the same species in clear water, at relatively low tempera- 
ture, the breathing habits are quite different and the insects ob- 
tain, I have no doubt, a goodly portion of their oxygen from the 
* This generalization is much too broad. The larvae of Culex impiger, 
for example, will swarm in water foul with decomposing animal matter, 
and so, possibly, will larvae of certain other species of Culex.—L. O. H. THE COMMON MOSQUITO 
89 
water itself. Just how they do this I am not prepared to say. 
One thing may be considered as certainly established by this 
series of observations : the insect can and does hibernate in the 
larval stage, if this is not, indeed, the prevailing method. Mr. 
Brakeley has scoured the swamps for miles about within the last 
few weeks, and wherever he found pitcher plants almost or quite 
every leaf had its supply of wrigglers. It is not, therefore, a local 
phenomenon. Nor is it even suggested that pitcher plants alone 
furnish breeding-places where the larv;e hibernate ; but they are 
remarkably safe resorts, protected to a very marked extent from 
natural enemies. Is there any relation between plant and insect, 
whereby the plant receives a benefit ? Do the wrigglers in any 
way i > re vent a foulness of the water from the insect fragments 
until the plant has absorbed what it needs ? 
It is noticeable that during the whole winter only a single ex- 
ample of Culex pungens was taken in the barns, storehouses, or 
cranberry-sorting rooms, though they were diligently sought. 
Anopheles punctipennis were found quite abundantly—between 
twenty and thirty specimens having been taken on the windows 
of the sorting rooms ; but no Anopheles larvse were found in any 
of the collected leaves. As a. Jerseyman, Mr. Brakeley ordinarily 
pays little attention to mosquitoes, but he could not easily over- 
look Anopheles, did it occur in any numbers in summer. He 
says that it does not, and that he has never seen as many during 
his years of residence in the Pines as he did this past winter. 
My own experience is similar. I remember that about three 
years ago I was annoyed by Anopheles very early in the year in 
my store-room in the basement of the Station Building. Later 
on I saw nothing of them, and I can say positively that the spe- 
cies of this genus form no part of the often considerable swarms 
in and near New Brunswick. 
In the cellar of my residence I took Culex pungens, female, 
March 22d, flying. It could not well have developed there, and 90 
MOSQUITOES 
of course there can be no doubt that the species hibernates as an 
adult as well as in the larval stage. 
These pitcher-plant leaves contain, besides mosquito larvae 
of this species, considerable numbers of other larvae, which Mr. 
Brakeley succeeded in breeding. Some examples submitted to 
Mr. C. W. Johnson he pronounced to be Aedes fuscus O. S., a 
species by no means commonly observed. 
The present series of notes are not by any means a complete rec- 
ord of the observations made on the wriggler colonies at New 
Brunswick and in the Pines, and they are not even ended ; but 
they will serve to call attention to one or two heretofore unob- 
served facts. They also contain a suggestion. Is it not prob- 
able that the mosquitoes that swarm in Alaska and in arctic 
regions may pass the winter in the larval stage, frozen in the solid 
ice, ready, when the melting time comes, to mature rapidly? 
Hiding-places for adults are occasionally somewhat scant in 
such regions, and the swarms are said to be even more numerous 
and vicious than they are in New Jersey. 
[Note.—Since this matter was put in type, Dr. Smith writes me that 
from recent roarings he is led to believe that most of his statements, 
especially with regard to the ability of larvae to remain under water a 
long time, refer to Aedes and not to Culex.—L. O. H.] IV 
The Malarial Mosquitoes of the Genus 
Anopheles 
TO physicians and others who are investigating the 
malarial conditions of a given neighborhood it 
becomes very important to know everything con- 
nected with this most noxious genus of insects. Not only 
is it necessary to be able to recognize them in every stage 
of their existence, but also to know the character of the 
pools in which they will be found in their early stages, 
since much time may be wasted in searching for them in 
places where they could not possibly occur, or in which 
they are not likely to be found. This point must be borne 
in mind, therefore, by those who, looking through this 
chapter, think that the writer has gone into the subject 
with apparently unnecessary detail. 
The genus Anopheles was founded by Meigen in 1818. 
The first reference to its early stages which is to be found 
in literature is in a paper entitled “ Description of a New 
Fish which I found in the water of the basin of S. Mag- 
loire of the Fauxbourg 8. Jaques at Paris, which can be 
called an Aquatic Caterpillar,” published in Paris in 1754 
by an observer who possessed the euphonious name of 
91 92 
MOSQUITOES 
Joblot. He figures the larva, which is recognizable as 
that of Anopheles. The Hutch observer, Meinert, gave 
the next accurate description and figure of the larva in 
1880, and other descriptions and figures were published 
by the Italian, Eicalbi, in 1899, and the Englishman, Giles, 
in 1900. The various stages of one of these species were 
described and figured in 1900 by the Italian, Grassi, and 
by the present writer. At the time I published these ob- 
servations, I supposed that I was the first person in Amer- 
ica to have seen Anopheles larvae, but Dr. Charles Sedg- 
wick Minot, of the Harvard Medical College, wrote me, 
after seeing the first edition of Bulletin 25, that he raised 
Anopheles twenty-five years or more ago without suspect- 
ing its identity. At that time Dr. Minot was much in- 
terested in entomology. He has since hunted up his old 
notes, and has published an account of his early observa- 
tions in the journal of the Boston Society of Medical 
Sciences, vol. v., January, 1901. 
The species which I studied in full in the summer of 
1900, and which was treated in my Bulletin 25 as Anophe- 
les quadrimaculatus Say, has been definitely decided to 
be identical with the Anopheles maculipennis of Europe.* 
* Osten Sacken, Entomologists' Monthly Magazine for December, 
1900, pages 281-283, shows that Anopheles claviger Fab. has no exist- 
ence. It never existed either as a type specimen, or as a scientific con- 
cept of a species. The correct name, therefore, of the common Anoph- 
eles of northern and central Europe is Anopheles maculipennis M., of 
which our American A. quadrimaculaUis Say, is a synonym, as has been 
shown by Theobald. Rulhe wrote in Oken’s Isis (1831, p. 1203), as 
pointed out by Osten Sacken in the above article, as follows : 
“Anopheles maculipennis M. is not uncommon in the Mark Branden- 
burg, in localities where water is abundant ; for instance, it is quite THE MALARIAL MOSQUITOES 
93 
Dr. IV. S. Thayer saw the European species in Grassi’s 
laboratory in Italy, and on his return to this country told 
me that he thought the two forms were identical; and 
the English student, F. V. Theobald, who is monograph- 
ing the mosquitoes of the Old World for the British Mu- 
seum, has studied a large series of specimens from this 
country and has decided that the European and American 
forms are identical. This at once suggests the interesting 
question as to whether this abominable creature was in- 
troduced from Europe to America or the reverse. It is 
quite within the bounds of possibility that malaria was 
originally an European disease and that not oidy was the 
disease itself carried from there on sailing vessels, but 
the mosquitoes which propagate it as well, at least to 
America. 
The Life History of Anopheles maculipennis. 
Tlie Adult.—The accompanying- illustration (Fig. 15) 
will show very well the general appearance of the 
adult insect. It is a rather large mosquito and is very 
bloodthirsty. It is attracted to the house in numbers. 
The differences between the males and females are 
well brought out in Fig. 15, and the striking feathery 
antennae and palpi of the male render it very conspic- 
uous. The wing markings and the color of the palpi 
differentiate this species from our other species of 
common about Frienwalde in midsummer. Its sting is more painful 
than that of any gnat I know, and has a much more pernicious effect. 
During a botanical excursion of several days which I made with some 
of my pupils, I noticed that the sting produced deep purulent wounds, 
which it took several weeks of careful medical treatment to heal.” 94 
MOSQUITOES 
Anopheles, and the long palpi of the female at once 
distinguish it from all species of Culex. 
Besting Position.—Owing to the publication of a field 
sketch made at Sierra Leone by a member of the Boss ex- 
pedition, the writer has been much interested in watch- 
ing the resting positions of the adult insects. He finds 
that when resting upon a horizontal surface—such as the 
ceiling of a room or the covering of breeding-jars—the 
insect clings with its four anterior legs in a nearly per- 
pendicular position, its beak thrust forward toward the 
surface to which it clings. The hind legs are frequently 
in motion, but as a rule hang downward with more or less 
of a bend at the knee joint (femero-tibial articulation). 
When resting upon a perpendicular surface, however— 
such as the side wall of a room or the side of a breeding- 
jar—the body is held only at a comparatively slight angle 
from the surface. Sometimes it is nearly parallel with 
the surface. At other times it assumes an angle of 10° 
to 20° (occasionally even as great an angle as 30° to 40°), 
the proboscis being held nearly in line with the body. 
Here again the insect supports itself by the four anterior 
legs, the hind leg dangling down with more or less of a 
bend at the knee. This position is common to both males 
and females, and is illustrated in Fig. 13. When the 
body is held parallel, it will generally be found that one 
of the middle or hind legs has been broken off. They 
are very delicate and readily break. 
Tlie writer lias taken the liberty of having1 Figure 14 
engraved from a drawing sent him by Mr. C. 0. Water- 
house of the British Museum. Mr. Waterhouse made the Fig. 13. — Resting Position of 
Anopheles ; enlarged. (Author’s 
illustration.) 
Fig. 14.—Resting Position of 
Anopheles above, Culex be- 
low ; enlarged. (From 
sketch by C. O. Water- 
house.) 96 
MOSQUITOES 
drawing himself and wrote : “ Whatever may be the 
attitude of Anopheles, it is all in one line. Culex is angu- 
lar, humpbacked.” 
Note of Female.- The peculiar hum of the mosquito is 
well known. There is a distinct difference between the 
Fig. 15.—Anopheles maculipennis, male at left, female at right; en- 
larged. (Author’s illustration.) 
hum of Anopheles maculipennis and that of the com- 
mon species of Culex, in that the former is noticeably 
lower in tone. The note of Culex as it approaches the 
ear is high in pitch ; that of Anopheles is certainly sev- THE MALARIAL MOSQUITOES 
97 
eral tones lower and of not so clear a character. In 
quality it is something between the buzzing of a house 
tiy and the note of Culex. Mr. Pratt states that he can at 
once distinguish the two genera in this way as he is sit- 
ting reading in the house, and the writer feels quite sure 
Fig. 16.—Egg Mass of Anopheles maculipennis; enlarged. (Author’s 
illustration.) 
after listening to them in breeding-jars that the statement 
is correct. 
These observations have been made with an abundance 
of material, nearly 100 adults having been under obser- 
vation. 
The Eggs.—The well-known and often-mentioned raft- 
sliaped masses of eggs of Culex are not even remotely 98 
MOSQUITOES 
resembled by the Anopheles ovipositions, and the indi- 
vidual eggs are equally dissimilar. In the accompany- 
ing illustration (Fig. 16) the egg mass of Anopheles is 
illustrated for comparison with Fig. 7. In Culex from 
200 to 400 eggs are laid in a mass ordinarily shaped like 
a pointed ellipse, convex below and concave above, all 
the eggs perpendicular, and stuck closely together at the 
sides by some gummy secretion, and arranged in rows. 
The mass with Anopheles, however, is laid loosely upon 
the surface of the water, each egg lying upon its side 
instead of being placed upon its end as in the egg mass of 
Culex. They are not attached together except that they 
naturally float close to each 
other, and there are from 40 
to 100 eggs in each lot. In 
Culex pungens the individual 
egg is 0.7 mm. long and 0.10 
mm. in diameter at the base. 
It is slender, broader, and 
blunt at the bottom, slenderer 
and more pointed at the tip. 
The tip is always dark grayish 
brown in color, while the rest 
is dirty white. The egg of 
Anopheles when seen from 
above is of rather regular el- 
liptical outline, the two ends having practically the same 
shape; seen from this side, it is strongly convex below 
and nearly plane above ; seen from below, it is dark in 
color, and when examined with a high power is seen to 
Fig. 17.—Individual Eggs of 
Anopheles maculipennis, from 
below at left, from above at 
right ; greatly enlarged. (Au- 
thor’s illustration.) THE MALARIAL MOSQUITOES 
99 
be covered with a reticulate hexagonal sculpturing. At 
the sides, in the middle, there appears a clasping mem - 
brane with many strong transverse wrinkles. Seen from 
above, the egg is black except for a clasping membrane 
which nearly meets on the middle line in the middle 
third of the body, but retires to the extreme sides for the 
anterior and posterior thirds. At each end the color is 
lighter, with a group of from 5 to 7 minute dark circular 
spots. It is 0.57 mm. long. Eggs laid April 26th hatched 
April 30th. Others laid May 13th and 14th hatched May 
16th and 17tli. 
Tlie Larva.—The larva is quite as unlike that of Culex 
pungens as is the egg. It differs in structure, in its food- 
habits, and in its customary position, so markedly, that it 
can at once be distinguished with the utmost ease. The 
larva of Culex, it will be remembered, conies to the sur- 
face of the water to breathe, thrusting its breathing tube 
through the surface layer and holding its body at an an- 
gle of about forty-five degrees with the surface of the 
water. While in this position its mouth-parts are in mo- 
tion and it is taking into its alimentary canal such minute 
particles as may be in the water at that depth, but these 
are naturally few in number and the larva descends at 
frequent intervals toward the bottom to feed. The want 
of oxygen, however, causes it to wriggle up again to the 
surface at very frequent intervals. Its specific gravity 
seems greater than that of water, so that it reaches the 
surface only by an effort, and the writer has already 
pointed out, in the case of Culex pungens, that when the 
larva becomes enfeebled and is not strong enough to 100 
MOSQUITOES 
wriggle up to the surface, it drowns. Feeding as it does 
at the bottom upon the heavier particles which sink, its 
specific gravity is explained. The larva of Anopheles 
maculipennis, however, habitually remains at the surface 
of the water. Its breathing tube is very much shorter 
than that of Culex, and its body is held not at an angle at 
the surface, but practically parallel with the surface and 
immediately below the surface film, so that portions of 
its head, as well as its breathing tube, are practically out 
Fig. 18.—Young Larva of Anopheles maculipennis ; enlarged. 
(Author’s illustration.) 
of the water. Its head rotates upon its neck in a most ex- 
traordinary way, so that the larva can turn it completely 
around with the utmost ease, and feeds habitually with 
the under side of the head toward the surface of the 
water, whereas the upper side of the body is toward the 
surface. In this customary resting position the mouth 
parts are working violently, the long fringes of the 
mouth-parts causing a constant current toward the mouth 
of particles floating on the surface of the water in the 
neighborhood, which thus gradually converge to this THE MALARIAL MOSQUITOES 
101 
miniature maelstrom and enter the alimentary canal. The 
spores of alga), bits of dust, minute sticks, bits of cast lar- 
val skins, everything 
in fact which floats, 
follow this course, and, 
watching the larva un- 
der the microscope, 
they can plainly be seen to pass 
through the head into the thorax 
until they are obscured by the 
dark color of the insect’s back. 
Occasionally, too large a frag- 
ment to be swallowed with ease 
clogs the mouth. Sometimes it enters the mouth and 
sticks. In such cases the head of the larva revolves 
with lightning-like rapidity and the fragment is nearly 
always disgorged, 
although some- 
times it is swal- 
lowed with an evi- 
dent effort. Since 
the Anopheles lar- 
va feeds only upon 
these light, floating 
particles, its spe- 
cific gravity is near- 
ly that of the water 
itself, and it supports this horizontal position just beneath 
the surface film with comparative ease, and, in fact, with- 
out effort, the tension of the surface film itself being hardly 
Fig. 19. -Half-grown Larva 
of Anopheles maculipennis; 
enlarged. (Author’s illus- 
tration.) 
Fig. 19a.—Same stage of 
Culex ; enlarged. (Au- 
thor’s illustration.) 102 
MOSQUITOES 
needed to hold it. It requires an effort, in fact, for the 
Anopheles larva to descend (which it apparently never 
does up to the period of the final larval stage, except 
when alarmed), while it requires an effort for the Culex 
larva to ascend. 
Structurally the differences between the half-grown 
larvae of Culex and Anopheles are well shown in Figs. 19, 
19a, and 20. The great size of the head of Culex, as con- 
trasted with the small head of Anopheles, is a most strik- 
Fig. 20.—Half-grown Larva of Anopheles maculipennis; enlarged. 
(Author’s illustration.) 
nig difference. The very long respiratory siphon (as Miall 
calls it) of Culex contrasts markedly with the short one 
of Anopheles. The arrangement of the hairs is entirely 
different; the branching of the hairs of Anopheles, as 
contrasted with the simple hairs of Culex and the little 
paired star-shaped (apparently branchial) tufts on the 
dorsum of Anopheles, is entirely absent with Culex. 
The flaps at the tail end of the body are similar in num- 
ber, but are held in a somewhat different position. THE MALARIAL MOSQUITOES 
103 
The larvae first studied—those which hatched from the 
eggs on April 30th—grew very slowly for a number of 
days. This was partly owing to cool weather in the early 
part of May, and partly, I believe, to the absence of 
proper food. They were reared in glass jars of water, with 
sand at the bottom and a willow twig rooting in the sand. 
Fig. 21.—Full-grown Larva of Anopheles maculipennis showing head 
upside down, with top of head above, at left; greatly enlarged. (Au- 
thor’s illustration.) 
As above noted, they swallowed every small particle float- 
ing1 on the surface of the water, and the dark coloration 
shown in Fig. 18 was largely due to the fact that most of 
these food particles were dark colored. About the lOtli of 
May, the larvae having passed through two molts, a small 
quantity of the green algae growing on the lily ponds on 
the Department grounds was placed in the jar. The 104 
MOSQUITOES 
larvae commenced to thrive much better, grew rapidly, 
and the general color of the body changed to green. The 
description of the habits given above held well until after 
the last molt preceding the change to pupae. In this final 
larval stage, as shown in Fig. 21, the diameter of the 
thorax became much greater in comparison with the rest 
Fig. 22.—Head of Larva of Anopheles maculipennis, under side; greatly 
enlarged. (After Nuttall.) 
of the body. The larva was less marked, more incon- 
spicuous, and altered its feeding habits to some extent. 
After remaining at the surface of the water, feeding, as 
before, upon floating particles, for some time, it would 
wriggle violently and descend to the bottom, where it 
would remain frequently as long as ten minutes before 
reascending to the top. Its appetite was evidently so THE MALARIAL MOSQUITOES 
105 
great that it was not satisfied with the floating parti- 
cles, and when it descended to the bottom it mouthed the 
particles of sand, apparently swallowing the slime on the 
little stones and frequently even picking up quite a large 
sand pebble and then dropping it again. In this stage 
the individual which grew most rapidly remained only 
four days, and transformed to pupa on the morning of the 
Fig. 23.—Enlarged Head of Larva of Anopheles maculipennis, from side; 
greatly enlarged. (After Nuttall.) 
17tli, after a larval existence of sixteen days. The accom- 
panying figures of the larvae have been drawn with such 
care that detailed description will be unnecessary. They 
were drawn from life under the compound microscope. 
Some of the structures are puzzling, notably the organs 
occurring on the dorsum of the abdominal segments, 
shown most plainly in Fig. 20, and which look as though 
they might be spiracles until they are examined under a 106 
MOSQUITOES 
high power in the cast skin. The writer does not care to 
risk an expression of opinion as to their function, althoug h 
possibly it is known, and they jiossibly occur in other dip- 
terous larvae. In the early stages of the larvae they re- 
semble minute branchial tufts, but no tracheal connection 
has been found. 
The Pupa.—The accompanying figure (Pig. 24) well rep- 
resents the differences between the pupa of Culex and 
Fig. 24.—Pupa of Anopheles at right; Culex at left; enlarged. 
(Author’s illustration.) 
that of Anopheles. In this stage the insects of the two 
genera are not so markedly different as in the larval stage. 
Structural differences need not be described, as they are 
sufficiently shown in the illustration. The eye will at 
once be caught by the difference in position, the pupa of 
Culex resting in a more perpendicular attitude than that 
of Anopheles ; and the marked difference in shape between 
the respiratory siphons, which issue from the thorax in- THE MALARIAL MOSQUITOES 
107 
stead of from the anal end of the abdomen, will at once 
be noticed. The pupa of Anopheles is quite as active, 
when disturbed, as is that of Culex. If one touches the 
surface of the water near it with the finger, the pupa at 
once wriggles violently away, returning shortly to the 
surface for air. 
The duration of the pupal stage in Anopheles varies 
according to the weather. Five days was the minimum 
observed during June, although several specimens re- 
mained in this stage for ten days. The adults issue as 
do those of Culex. 
The entire life round, therefore, of Anopheles maculi- 
pennis in the generation studied by the writer is as follows: 
egg stage, three days; larval stage, sixteen days; pupal 
stage, five days ; making a total period in the early stages 
of twenty-four days. It should be stated, however, that 
during the early larval existence, toward the end of May 
there occurred nearly a week of cool weather, so that it is 
certain that in the hot season in July and August the 
growth and transformations will be more rapid. It will be 
remembered that the writer traced Culex pimc/ens through 
an entire generation in the latter part of June, in ten days. 
European Observations on the Same Species. 
Nuttall and Shipley state that when the eggs are first de- 
posited they are white, but that they soon blacken. They 
are boat-shaped, and one end is slightly deeper and fuller 
than the other. The thickening at the edge, which in pre- 
vious paragraphs was called the clasping membrane, is 108 
MOSQUITOES 
composed of air chambers, and is used to keep the boat- 
shaped egg with its fiat surface uppermost. The English 
writers have observed that when the eggs have been much 
rubbed, the delicate membrane splits off and the egg ap- 
pears with a glistening black surface like patent leather. 
They have noted also that when the 
egg, as frequently happens, is drawn 
by capillary action a little way up from 
the water on a leaf, the head or blunt 
end always points downward, so that 
when the larva emerges it drops into 
the water, and not up in the air. 
Grassi says that the eggs of this 
species lie in groups of from three to 
twenty, side by side, like a bridge of 
boats, but Nuttall and Shipley find 
them in open pools in Great Britain 
scattered about. According to these 
observers the eggs hatch on the second or third day after 
being laid, depending on the temperature, the young issu- 
ing through a circular split near the blunt end of the egg. 
They also state that eggs which were dried less than five 
days did not hatch. Full and detailed accounts of the 
anatomy of the larva and pupa are given by the English 
writers in a paper entitled “ The Structure and Biology 
of Anopheles ” (A. maculipennis) in the Journal of Hygiene 
vol. i., No. 1, January, 1901; this article is beautifully 
illustrated. 
Fig. 25.—Head of Full- 
grown Larva of 
Anopheles puncti- 
pennis ; enlarged. 
(Author’s illustra- 
tion.) THE MALARIAL MOSQUITOES 
109 
Natural Breeding Places of Anopheles. 
A number of the natural breeding-places of Anopheles 
maculipennis and A. pundipennis have been found by the 
writer in the United States. They have always been found 
in more or less permanent pools of water, either in the bed 
of an old canal or in spring-fed woodland streams, or in 
the side pools or shallows of field springs, or in artificial 
excavations filled with surface water. In such places, 
when supplied with a certain amount of green scum, the 
little larvae will often be found resting at the surface of 
the water, and occasionally darting from one spot to 
another. 
The larvae of A. pundipennis differ from those of A. rna- 
culipennis largely in the marking of the head, as indicated 
in the accompanying figure. The temperature of the 
water which they inhabit varies from 18° C. to 25° C- 
Nuttall and Shipley state that in England these larvae 
are to be found in pools, ditches, backwaters of rivers 
and canals, and in other slow-flowing waters; almost in- 
variably in such waters as are clear and very rarely in im- 
pure or brackish water. In their experience, they prefer 
pools which are not shaded by trees, although I have 
found them in this country on several occasions in a 
dense shade. They are very rarely found in water con- 
tained in barrels and troughs and fountain basins, and 
they are very rarely found in the same water with the 
larvae of Culex. Mr. E. E. Austin, in “ The Report of 
the Proceedings of the Expedition for the Study of the 110 
MOSQUITOES 
Causes of Malaria at Sierra Leone,” states that on 
August 26, 1899, Dr. Prout and Dr. Berkeley found 
Anopheles larvae mingled with those of Culex in a tub of 
Fig. 26.—Female of Anopheles punctipennis ; enlarged. (Author’s illus- 
tration.) 
water in a yard at tlie Sanitary Office. With one excep- 
tion this is the only instance in which he found Anoph- 
eles breeding elsewhere than in a roadside puddle or 
ditch. Dr. C. W. Daniels, in the “ Royal Society Reports THE MALARIAL MOSQUITOES 
111 
to the Malarial Committee,” December 31, 1900, says that 
in Africa either larvae may be found alone, but in many 
situations both are found together and even several spe- 
cies of each. At least five species of Culex were found 
with Anopheles larvae. “ The less the movement of the 
water the greater the probability of Culex larvae being 
also found, and in a grass-grown river, the Anopheles 
Fig. 27.—Male of Anopheles punctipennis, from side ; enlarged. (Orig- 
inal.) 
larvae will be more abundant near the stream and the 
Culex larvae near the bank.” 
Nuttall, Cobbett, and Strangeways-Pigg, in England, 
captured Anoplieles nine times with Culex in ponds and 
also took them with Culex in ditches in which the water 
scarcely flowed, in water-logged boats, in stone troughs, 
and in fact found them fourteen times together with 112 
MOSQUITOES 
Culex and ten times with fish. Dr. F. A. Young, a Brit- 
ish army surgeon, has told me that in his experience if 
the larvae of Culex and Anopheles are put into the same 
vessel those of Anopheles will disappear. 
Lieutenant-Colonel Yerbury says that “ the natural 
home of Anopheles seems to be damp swampy ground, 
but not necessarily so wet as a marsh or a fen.” Grassi 
and Ficalbi state that A. maculipennis is most frequently 
found in Hat land in Italy, the larvae requiring clear water 
rich in vegetable food. E. E. Austen found in Freetown 
that Anopheles larvae were in stagnant puddles, varying 
from a foot to several feet, at the sides of the streets, but 
many were met in the still water in little bays at the side 
of slowly running shallow ditches. Whether the water 
was clear or muddy seemed to make no difference, but 
green algae were nearly always present and in some pud- 
dles tadpoles were numerous. Dr. H. A. Yeazie, of New 
Orleans, has found Anopheles larvae in the ponds out in 
the suburbs in the swamps back of the city. Dr. Wol- 
dert, of Philadelphia, has found the larvae of both A. ma- 
culipennis and A. punctipennis breeding in the same nar- 
row and slowly flowing stream of fresh water, which 
drained a marshy district formed by a railroad embank- 
ment. He found larvae in this stream from June 19th to 
November 11th and located live localities within the city 
limits of Philadelphia where Anopheles breeds. Grassi, 
at Metaponto, Italy, is said to have found Anopheles in 
brackish water. THE MALARIAL MOSQUITOES 
113 
The North American Species of Anopheles. 
So far as known at the present time we have but three 
species of the malarial genus in the United States, namely 
A. maculipennis Meigen (equals A. quadrimaculatus Say), 
A. punctipennis Say, and A. crucians Wied., although Mr. 
Theobald, in his monograph, which will include the mos- 
quitoes of the world, will describe forty-two species of this 
genus, and possibly more. 
A. maculipennis is a rather insignificant species, 
which is well illustrated in Figure 15, its wings being 
nearly clear, but marked with four rather small dark 
spots composed of groups of darker scales. Its palpi are 
entirely black. 
A. punctipennis is our handsomest species, and has a 
yellowish white spot occupying about three-fourths of 
the length of the front margin of the wing. The scales 
on the last vein are white and those at each end black. 
A. crucians has the palpi marked with white at the 
bases of the last four joints, and the scales of the last 
wing vein white, marked with three black spots. The ac- 
companying figures will enable a much readier differentia- 
tion of this species than will any description. 
As to distribution, A. maculipennis and A. punctipennis 
are found almost everywhere in this country. I have seen 
specimens of A. maculipennis from New Hampshire, Con- 
necticut, New York, District of Columbia, Maryland, Vir- 
ginia, Florida, Texas, Louisiana, Indiana, Illinois, Min- 
nesota, and Oregon. Dr. A. S. Packard has recorded its 114 
MOSQUITOES 
occurrence at Brunswick, Me., in 1861-63. A. punctipen- 
nis I have seen from Vermont, Massachusetts, Connec- 
ticut, New York, New Jersey, Pennsylvania, District of 
Columbia, Maryland, Mississippi, Texas, New Mexico, 
Fig. 28.—Anopheles crucians, adult female; enlarged. (Author’s il- 
lustration.) 
Kansas, Illinois, Indiana, Oregon, and Jamaica (13. W. I.). 
Professor C. H. Fernald writes me that lie lias taken it at 
Orono, Me., and that it is rather common at Amherst, 
Mass. A. crucians I have seen only from the District of THE MALARIAL MOSQUITOES 
115 
Columbia, Virginia, Georgia, Florida, and Louisiana. 
The last species therefore seems to be a more southern 
form, while the other two have a very wide distribution, 
including a considerable distribution to the North. 
Dr. W. N. Berkeley, of New York, in the Medical Record 
for January 26, 1901, states that A. punctipennis is abun- 
dant in certain parts of Bronx Borough, particularly Je- 
rome Park. A. maculipennis appears to be universally dis- 
tributed in the suburbs of New York. Since he learned 
how and where to look for it, he found it nearly co-exten- 
sive with all the cases of fresh malaria that he had the 
leisure to go to and look into. It was present in such 
widely separated places as Passaic, N. J., Tuxedo, New 
York, Fordham, and Jerome Park, Mount Yernon, and 
East Hampton. In East Hampton, on the authority of 
Dr. F. P. Holley, Dr. Berkeley says that until the summer 
of 1900 no native malaria had been known at East Hamp- 
ton, in spite of a large number of malarial mosquitoes. He 
explains this in two ways : (1) That no malarious case had 
recently been imported there to start an infection among 
the mosquitoes, and (2) that the nights are cold, the 
night temperature being considerably below the mini- 
mum (77° F.) at which the malarial bodies are believed, 
according to Koch, to develop in the stomach of the mos- 
quito. The Anopheles was always found in buildings, 
oftenest on walls and ceilings of recently used bedrooms, 
and far most abundantly in the foul and ill-ventilated 
bedrooms of the poor. The house females were usually 
gorged with blood, and sluggish enough to be easily 
caught. They were numerous in outdoor privies. He 116 
MOSQUITOES 
never found them out of doors. Males were caught in 
houses also, but generally only one male to twenty 
Fig. 29.—Anopheles argyritarsis, adult female; enlarged. (Original.) 
females. He caught Anopheles in a house in the Bronx on 
November 6tli and on Christmas day. In a draughty, cold, 
underground cellar in the same house he caught a dozen THE MALARIAL MOSQUITOES 
117 
or more, all females, mostly punctipennis and a few 
maadipennis. They were in complete hibernation, and 
had to be knocked from the wall as if dead, but revived in 
a glass tube under the warmth of the hand. So far as Dr. 
Berkeley’s observations go, the hypothesis of the Italian 
workers that only fertilized females survive the winter, is 
true. 
Dr. Theobald Smith, of the Bussy Institute, has pub- 
lished a paper entitled, “ Notes on the Occurrence of 
Anopheles punctipennis and A. quadrimaculatus in the Bos- 
ton Suburbs,” in the Journal of the Boston Society of Medi- 
cal Sciences (vol. v., pp. 321-324, January, 1901) in which 
he shows that he has found both species at Jamaica 
Plain, although malaria does not exist there. The oc- 
currence of the Anopheles, unless their breeding-places 
are wiped out, shows that if malaria patients should come 
to Jamaica Plain, the disease would rapidly spread. 
The species Anopheles argyritarsis, mentioned in Chap- 
ter X. and illustrated in Fig. 29, is a very beautiful species 
which occurs in Cuba, where it has been captured by Dr. 
James Carroll of the Army Yellow-fever Commission. 
Food of Anopheles Larvae. 
As already indicated, the principal food of the larvae of 
Anopheles seem to be the spores of algae, but, as we have 
pointed out, they will swallow anything which floats on 
the surface of the water. I have seen one nearly choke to 
death in the attempt to swallow a good sized bit. The 
English observer, Dr. Daniels, in the course of his in- 118 
MOSQUITOES 
vestigations in Africa, found that the contents of the 
intestines of the larvae are mainly vegetable matter—in 
some cases entirely so. Occasionally limbs of minute in- 
sects or crustaceans were found, as well as scales of mos- 
quitoes or other insects. “ On watching them feeding it 
is seen that all minute particles are drawn to the mouth, 
but many of them are rejected. This rejection is some- 
what arbitrary, as a particle at first rejected is often 
subsequently swallowed. Among the bodies seen to be 
swallowed I have seen living minute crustaceans and 
young larvae, both of Anopheles and Culices, but as a 
rule living animals either escape or are rejected.” Chris- 
tophers and Stephens state that in their observations in 
Sierra Leone the food of the majority of the Anopheles 
larvae seemed to be a unicellular protococcus. 
Length of Life of Adult Anopheles. 
Physicians studying- the adults in order to determine 
the duration of the different stages of the malarial organ- 
ism have occasion to keep adult Anopheles alive in con- 
finement. This has been accomplished up to eight weeks 
by feeding them occasionally upon sliced bananas or 
other fruits. The adults live for very considerable spaces 
of time, as has, in fact, been pointed out in the first chap- 
ter of this book. In colder climates the adults hibernate 
often in houses, and in tropical climates the adults live 
through the dry spell to lay tlicir eggs when the rains 
come and breeding-pools are re-established. The hiber- 
nation of Anopheles in this country has been frequently THE MALARIAL MOSQUITOES 
119 
observed. Dr. W. S. Thayer has informed me that he 
found Anopheles crucians and Anopheles maculipennis 
hibernating in enormous numbers in barns near New 
Orleans, and in early February, 1901, Dr. H. A. Yeazie 
wrote me that Anopheles punctipennis had been captured 
in his house, in his office, and in the show-window of a 
shop on Canal Street. Dr. A. Hassel, of Baltimore, found 
Anopheles punctipennis in his house in January, 1901, and 
during this month his son and daughter developed ma- 
laria, the diagnosis being perfectly confirmed by blood 
examination. About a week before this were several 
warm days. Probably the mosquitoes had been hibernat- 
ing in his house and had become active on account of the 
warm spell. 
How Anopheles Bites. 
It is the experience of a number of observers, as re- 
corded, that the bite of Anopheles is more insidious 
than that of Culex. When not occurring in numbers, 
they may bite a person while asleep and not be detected. 
This point is especially used in answering the broad and 
general statement that malaria may be developed where 
there are no mosquitoes. Professor E. W. Hilgard, of 
the University of California, wrote me in September, 
1900, to the effect that in the coast marshes of the Missis- 
sip pi Sound, he has seen Anopheles in great numbers, 
probably punctipennis. Down there this insect is called 
the black mosquito, and, as Professor Hilgard states, “ is 
noted for biting without a moment’s reflection, plunging 120 
MOSQUITOES 
head foremost right into you, while Culex always medi- 
tates for a while before biting.” Professor Hilgard 
further stated that in those marshes there is little or no 
malaria and that he had been exposed there for weeks 
without injury, nor did the inhabitants complain of chills 
or fever. But in the Arkansas bottoms it took him only 
a few days to succumb, and the natives “luxuriated in 
‘ ague cake.’ ” y 
Mosquitoes and Yellow Fever ; Mosquitoes 
and Flliariasis 
IN 1881, Dr. Carlos Finlay, of Havana, noticed a cor- 
respondence betAveen the abundance of mosquitoes 
and a period of increase of yelloAv fever in the 
autumn, Avliile during the summer yelloAv fever had been 
scarce and mosquitoes also scarce. This suggested to 
him the idea that mosquitoes are responsible for the 
transfer of the disease, and he conducted certain experi- 
ments in which he claimed to have transmitted the 
disease by the bites of the mosquitoes which had previ- 
ously sucked the blood of persons suffering with the 
disease. Carrying on his idea further he proposed a 
plan of inoculating non-immunes by the bites of infected 
mosquitoes, on the theory that a mild type of the disease 
Avould be produced Avliich Avould afterward be protective 
against reinfection of a more severe character. 
Dr. Finlay’s theory was received with interest by phy- 
sicians and investigators, but Avitli a very pronounced 
general incredulity. His experimental Avork did not 
seem to have been definite enough to attract confidence 
to his conclusions, nor Avas there enough of it. It is 
121 122 
MOSQUITOES 
rather strange that his published papers did not excite 
sufficient interest to induce other investigators to under- 
take any experimental work in the same direction. This 
fact in itself shows plainly the almost perfect incredu- 
lity with which they were received. When, however, 
the beautiful results of the malarial investigators had 
become generally accepted and it was shown beyond all 
peradventure that not only do certain mosquitoes carry 
filiaria, but also that some of them are necessary second- 
ary hosts of the malarial micro-organisms, then it was 
that a few people began to think of Dr. Finlay and his 
theory. In the meantime, strong efforts had been made 
to find the cause of yellow fever. Several micro-organ- 
isms had been discovered and several investigators 
announced the probable discovery of the causative germ. 
Nearly all of these discoveries have been discredited by 
subsequent observations. The organism which has 
received the most support has been the Bacillus icteroides 
of Sanarelli, but down to a very recent date the insistent 
claim by the Italian investigator of the value of his dis- 
covery has been disputed by competent observers. 
Tlie occupation of the island of Cuba by American 
troops attracted the attention of Dr. Sternberg1, Surgeon- 
General of the Army, more strongly than ever before, to 
the subject of yellow fever, although he had long been an 
ardent investigator of the cause of the disease, and, in 
fact, was one of the Yellow-fever Commission who visited 
Cuba in 1879, in an effort to investigate scientifically and 
by modern bacteriological methods the causation of the 
fever. In this early Cuban residence he became ac- MOSQUITOES AND YELLOW FEVER 
123 
quainted with Dr. Finlay and with his mosquito theory, 
and therefore, under these late conditions and with the 
malaria case proven, he established a commission of army 
surgeons, composed of Major Walter C. Heed, Surgeon, 
U. S. A., Dr. James Carroll, Acting Assistant Surgeon, FT. 
Fig. 30.—Stegomyia fasciata, adult female; enlarged. (Author’s 
illustration.) 
S. A., Dr. Jesse W. Lazear, Acting1 Assistant Surgeon, 
U. S. A., and Dr. A. Agramonte, Acting Assistant Sur- 
geon, U. S. A., and instructed them to investigate the 
disease from the mosquito standpoint. The investiga- 
tions carried on by this commission during the early 124 
MOSQUITOES 
part of 1900 were extremely suggestive in their results. 
In the course of the investigations, both Drs. Carroll and 
Lazear were attacked by the disease. Dr. Carroll recov- 
ered, but Dr. Lazear died—another of the long list of 
martyrs who have suffered in the cause of scientific 
research. In this preliminary work, which Dr. Reed 
reported upon at the twenty-eighth annual meeting of 
the American Public Health Association, Indianapolis, 
Ind., October 23, 1900, it was shown that eleven non- 
immune individuals had been inoculated by the bites of 
the species then known as Culexfascialus, which had previ- 
ously fed upon blood of patients sick with yellow fever. 
Dr. Reed was able to report two positive results in which 
an attack of yellow fever followed the bite of a mosquito 
within the usual period of incubation of the disease. In 
one of the cases all other sources of infection could posi- 
tively be excluded. The results of this preliminary work 
were summed up in two conclusions: 1. Bacillus icte- 
roides Sanarelli stands in no causative relation to yellow 
fever, but when present should be considered as a second- 
ary invader in this disease. 2. The mosquito serves as 
the intermediate host for the parasite of yellow fever. 
The announcements made in this preliminary note ex- 
cited much attention. The scientific standing- of the in- 
vestigators, as well as the positive result announced in 
one of the cases, made the theory at once one of serious 
importance. Medical men, however, were inclined to wait 
for further developments before expressing an opinion. 
Their point of view was perhaps well summed up by the 
British Medical Journal, which stated that although the MOSQUITOES AND YELLOW FEVER 
125 
experiments “appear to show almost conclusively that the 
germ is conveyed by a special species of mosquito and that 
the insect becomes infected only after ten to thirteen 
days from the time of the ingestion of the germ, the ex- 
periments are really by no means conclusive. At the 
most they are suggestive.” 
But the investigators themselves were by no means 
satisfied with the proof which they had gained. They 
returned to Cuba in the autumn of 1900, and spent the re- 
mainder of the autumn and the whole winter in further 
experimental work. The results obtained were so posi- 
tive and striking that, with the permission of the Sur- 
geon-General, they presented an additional note before 
the Pan-American Medical Congress, held in Havana, 
February 4-7, 1901. This paper, presented by Major 
Eeed, records the details of the work done up to that 
time and announces its results. 
Aii experimental sanitary station was established in an 
open, uncultivated field, about one mile from the town of 
Quemados, Cuba, under the complete control of Major 
Eeed. The station was named Camp Lazear, in honor of 
the brave physician who went to his death in the early 
summer of 1900. A most careful series of experiments 
was carried on to see whether yellow fever can be con- 
veyed by fomites, that is, by personal contact with the 
clothes or belongings of yellow-fever patients. As is 
well-known, the consensus of opinion, both of the medi- 
cal profession and of others, is in favor of the conveyance 
of yellow fever in this way, and every effort is made to 
disinfect clothing and bedding shipped from ports where MOSQUITOES 
126 
yellow fever prevails. All articles of personal apparel are 
subjected to disinfection and, as everyone knows, during 
a time when the fever is epidemic in any of our Southern 
States even the mails are disinfected before being allowed 
to go North. There was further erected at Camp Lazear 
a small frame house with a cubic capacity of 2,800 feet, 
tightly ceiled and battened, provided with small windows, 
so as to prevent a thorough circulation of air through the 
house, and with wooden shutters to prevent the disinfect- 
ing qualities of sunlight. The windows were closed by 
permanent wire screens with a 5-millimetre mesh. The 
vestibule was protected by a solid door and a wire screen- 
door, and the inner entrance by a second wire screen- 
door. In this way the passage of mosquitoes into the 
room was effectually excluded. The average temperature 
was kept at 76.2° F. for a period of sixty-three days, and 
precaution was taken to maintain sufficient humidity of 
the atmosphere. On November 30tli, three large boxes 
filled with sheets, pillowslips, blankets, and so on, con- 
taminated by contact with cases of yellow fever and their 
discharges, were received and placed in the room. Most 
of these articles had been taken from the beds of patients 
sick with yellow fever in Havana. Many of them had 
been purposely soiled with the excretions of patients. 
These soiled sheets, pillowcases, and blankets were used 
in preparing the beds in which the members of the hos- 
pital corps slept. During sixty-three days this building, 
thus furnished, was occupied by seven non-immune per- 
sons. Three of them occupied the room each night for 
twenty days. Later a fourth box of clothing and bed- MOSQUITOES AND YELLOW FEVER 
127 
ding was added, some of it purposely soiled with the 
bloody stools of a fatal case of yellow fever. Two of 
them occupied beds from December 21st to January 
10th, every night, wearing the very garments worn by 
yellow-fever patients throughout their entire attacks, 
Fig. 31 .—Stegomyia fasciata, adult male; enlarged. (Original.) 
making use exclusively of their mucli-soilecl pillowslips, 
sheets, and blankets. At the end of twenty-one nights 
they went into quarantine (as had the former three) and 
were released five days later. Two other non-immunes 
occupied the same beds for twenty days more. The at- 
tempt therefore which was made to infect this building 128 
MOSQUITOES 
and its seven non-immune occupants during a period of 
sixty-three days was an absolute failure ; all seven were 
released from quarantine in excellent health. 
A precisely similar building was erected at Camp La- 
zear, which was known as the infected mosquito building. 
The door and windows were placed on opposite sides of 
the building so as to give a thorough ventilation. It was 
divided into two rooms by a wire screen partition extend- 
ing from floor to ceiling. All articles admitted to the 
building were carefully disinfected by steam before be- 
ing placed therein. Into the large room of this build- 
ing mosquitoes which had previously been contaminated 
by biting yellow-fever patients were admitted. Non- 
immunes were placed in both rooms. In the room in 
which mosquitoes were not admitted the experimentalists 
remained in perfect health. In the other room six out of 
seven persons bitten by infected mosquitoes came down 
with yellow fever. In all, of persons bitten by infected 
mosquitoes that had been kept twelve days or more after 
biting yellow-fever patients before being allowed to bite 
them, eighty per cent, were taken with the disease. 
The conclusions reached after this careful experimen- 
tation, have been summarized under eleven heads, as 
follows: 
1. The mosquito—G.fasciatus—serves as the intermedi- 
ate host for the parasite of yellow fever. 
2. Yellow fever is transmitted to tlie non-imnmne indi- 
vidual by means of the bite of the mosquito that has 
previously fed on the blood of those sick with this dis- 
ease. MOSQUITOES AND YELLOW FEVER 
129 
3. An interval of about twelve days or more after con- 
tamination appears to be necessary before the mosquito 
is capable of conveying the infection. 
4. The bite of the mosquito at an earlier period after 
contamination does not appear to confer any immunity 
against a subsequent attack. 
5. Yellow fever can also be experimentally produced 
by the subcutaneous injection of blood taken from the 
general circulation during the first and second days of 
this disease. 
6. An attack of yellow fever, produced by the bite of the 
mosquito, confers immunity against the subsequent injec- 
tion of the blood of an individual suffering from the 
noil-experimental form of this disease. 
7. The period of incubation in thirteen cases of experi- 
mental yellow fever has varied from forty-one hours to 
live days and seventeen hours. 
8. Yellow fever is not conveyed by fomites, and hence 
disinfection of articles of clothing, bedding, or merchan- 
dise, supposedly contaminated by contact with those sick 
with this disease, is unnecessary. 
9. A house may be said to be infected with yellow fever 
only when there are present within its walls contami- 
nated mosquitoes capable of conveying the parasite of 
this disease. 
10. The spread of yellow fever can be most effectually 
controlled by measures directed to the destruction of 
mosquitoes and the protection of the sick against the 
bites of these insects. 
11. While the mode of propagation of yellow fever has 130 
MOSQUITOES 
now been definitely determined, the specific cause of this 
disease remains to be discovered. 
A large supply of contaminated mosquitoes, carefully 
preserved, has been brought to Washington by Drs. 
Reed and Carroll and careful work is now being carried 
on in an effort to find the causative organism of the dis- 
ease. It seems quite probable that it will prove to be 
some sporozoon, following in a measure a somewhat 
similar life-round to that of the malarial organisms. 
It is interesting' to note that the very recently pub- 
lished “ Interim Report ” of Herbert E. Durham and the 
late AYalter Myers, to the Liverpool School of Tropical 
Medicine, based on observations on yellow fever in Bra- 
zil, in the course of which Dr. Myers died, just as did Dr. 
Lazear in Cuba, indicates the belief of these investigators 
in the causative effect of a small bacillus which they 
found in the organs of all fatal cases. They conclude 
that the yellow fever is not due to a protozoon, and with 
regard to the American results, they make the following 
comment: “ The endeavor to prove a man-to-man trans- 
ference of yellow fever by means of a particular kind of 
gnat, by the recent American Commission, is hardly 
intelligible for bacillary diseases. Moreover, it does not 
seem to be borne out by their experiments, nor does it 
appear to satisfy endemiological conditions.” It is 
obvious that this report of the English investigators was 
prepared before the final and more complete paper of 
the American Commission was read by Dr. Reed in Hava- 
na, and even with this granted, it was hardly fair in them 
to style the investigations of the Americans “ an endeavor MOSQUITOES AND YELLOW FEVER 
131 
to prove,” etc. The Americans were after the truth, and 
had no desire to learn anything but the truth, that is to 
say, they did not endeavor to substantiate any particular 
theory. 
As a result of the investigations, the Governor-General 
of Cuba, himself a medical man, General Leonard Wood, 
became so impressed with the accuracy of the conclu- 
sions that he authorized the promulgation of instructions 
to commanding officers in Cuba, relative to protection 
against mosquitoes and remedial measures in connection 
with their breeding-places. General orders were issued 
requiring the enforcement of the use of mosquito bars in 
all barracks, and especially in all hospitals, and the de- 
struction of the larvae by the use of petroleum on the water 
where they breed. (See Chapter VIII.) The medical offi- 
cer who makes the sanitary inspection at each post is 
charged with the supervision of the details of these pre- 
cautions. As a result, the writer understands that the 
prevalence of malaria has been greatly reduced in western 
Cuba, and it is hoped that with regard to yellow fever 
similar results will be shown during the coming year. 
The Yellow-fever Mosquito. 
Tlie particular species of mosquito which was used by 
Dr. Finlay in his original experiments, and which is the 
only form which has been shown bj7 our Army Commis- 
sion to transmit the disease, is the one which has been 
referred to in this country as Culex fasciatus Fabricius. 
It was so termed in the writer’s bulletin, entitled “Notes on 132 
MOSQUITOES 
Mosquitoes,” published as Bulletin 25, new series, of the 
Division of Entomology, of the United States Department 
of Agriculture, August, 1900, and has been so named in the 
published reports of the Commission. There now seems 
very good ground for the belief that the wide-spread 
Fig. 32.—Adult Male of Stegomyia fasciata from side ; enlarged. 
(Author’s illustration.) 
tropical mosquito usually referred to as Culex tceniatus of 
Wiedemann, is really a synonym of tliis species. It will 
be remembered that down to the present time we have 
no evidence that any other mosquitoes than those of the 
genus Anopheles transmit malaria, and that so far as 
known all species of this genus have this pathological MOSQUITOES AND YELLOW FEVER 
133 
characteristic. In the case of yellow fever, why should 
one species of Culex be able to transmit the disease and 
not another species, assuming, as it will be quite proper 
to assume, that since this capacity appears to be of generic 
importance with Anopheles, it would be of generic im- 
Fig. 33.—Body Scales from Stegomyia fasciata ; the broad one from a 
white stripe and the narrow one from a dark surface ; greatly en- 
larged. (From Photo-micrograph by Dr. Erwin F. Smith.) 
portance in the case of yellow fever ? It happens that the 
British Museum is investigating the mosquitoes of the 
world. Specimens have been sent to the expert, Mr. F. 
Y. Theobald, who has charge of the work, from all quar- 
ters of the globe, and Mr. Theobald has made a special 134 
MOSQUITOES 
study of the morphological features of these insects. 
Without knowing the results of the American Commission, 
Mr. Theobald had decided that Culex fasciatus or toeniatus 
is not to be contained in the genus Culex, but that on 
account of scale structure and other structural peculiarities 
it must be placed in another genus for which he has pro- 
posed the name of Stegomyia. A few other species for- 
merly placed in the genus Culex he also puts in this new 
genus of his, which arouses the presumption that they 
also may be capable of transmitting yellow fever. At all 
events, we have here a most interesting and suggestive 
co-relation between obvious structural peculiarities and 
pathological possibilities. 
Stegomyia fasciata, as we must now, at least for tlie 
present, call the only yellow-fever mosquito about which 
we are at all certain, is an inhabitant of the warmer por- 
tions of the globe. Mr. Theobald writes me that it occurs 
in abundance in Cuba and all the West Indies, and that 
he has had it from all the warmer countries, but not from 
arctic and temperate climates. He has it even in the 
warmer portions of Europe, from Italy, Greece, Spain, 
Portugal, Gibraltar, and Malta. He generalizes that it is 
found north and south of the equator to 38° north and 
south latitude. In the United States it is common in 
most of our Southern States. I have seen specimens 
from New Orleans, La. (Dr. H. A. Yeazie and Dr. W. S. 
Thayer), from Natchitoches, La. (Mr. C. W. Johnson), from 
Napoleonville, La. (Dr. L. E. Flannagan), from eastern 
Texas (Dr. A. E. Woldert), from Hot Springs, Ark. (Dr. 
A. W. Wright), from Pelham, Ga. (Mr. D. W. Coquillett), MOSQUITOES ANJJ YELLOW FEVER 
135 
and from as far north as Virginia Beach, Va. (Mr. F. C. 
Pratt). From the West Indies, I have seen specimens 
Fig. 34.—Larva and Pupa of Stegomyia fasciata, with enlarged parts; 
enlarged. (Original.) 136 
MOSQUITOES 
from the Isle of Pines (Mr. S. H. Scudder), from King- 
ston, Jamaica (Mr. C. W. Johnson), from Cuba (Drs. Reed, 
Carroll, and Lazear), and from Bluefields, Nicaragua (Dr. 
L. A. Wailes). Nearly all these places are well within 
the yellow-fever belt. Virginia Beach, the northernmost 
locality indicated, is only a short distance from Norfolk, 
Va., which in former years has suffered from yellow-fever 
epidemics. It must be said that the collections of mos- 
quitoes which have been made are more or less accidental 
and that no thorough means have been taken to ascertain 
the exact geographic range of this or any other species 
of mosquito. It is quite likely that thorough collecting 
would show the existence of this species at a more north- 
ern locality. In fact, if it should prove to be the only 
species of mosquito which is capable of transferring this 
fever, the epidemics of yellow fever in Philadelphia and 
New York, and even in New Haven and Providence, about 
the beginning of the last century, would indicate that at 
that time, at least, this mosquito had a more northern 
range, or at all events that it had been introduced at those 
points by sailing vessels coming from the South, and that 
it succeeded in breeding there at least for some part of a 
year. 
The insect itself is a very handsome one. The banded 
legs and the conspicuous silver stripes upon its thorax and 
abdomen render it rather readily recognizable. It is well 
shown in the accompanying illustrations. It breeds almost 
everywhere in standing water. So far as has been ascer- 
tained, it does not breed in brackish water. Dr. Flanagan 
sent me specimens in November, 1900, and wrote that the Fig. 35.—Mouth-parts of Larva of Stegomyia fasciata ; greatly enlarged. 
(Original, C. L. Marlatt, del.) 138 
MOSQUITOES 
bite of this species is worse in the autumn than in the 
summer, and that it breeds in cisterns, which, in that sec- 
tion, are in universal use for obtaining drinking-water. 
Mr. Pratt made some interesting observations on the 
species at an Atlantic Coast summer resort, in a latitude 
of about 3G° 50' N., and succeeded in obtaining the larvae 
and pupae, from which the accompanying drawings were 
made. At that point he also found it breeding in the 
rain-water tanks. Neither larva nor pupa differs greatly 
from that of the species of the genus Culex, the charac- 
teristics of which have been described in an earlier 
chapter. It may be of interest to note that before this in- 
sect was connected with yellow fever, I learned that in 
certain of the West Indies and in Louisiana it is known 
as the “day mosquito.” Dr. Veazie, of New Orleans, and 
Dr. St. George Gray, of St. Lucia, communicated this fact. 
The latter writes that it is very vigorous and troublesome 
in the early afternoon, from 12 M. to 3 p.m., after which it 
takes a rest until 9 or 10 r.M. 
It should be stated emphatically that it is probable that 
this species has a wide range south of Mason and Dixon’s 
line, and that it probably occurs everywhere in what is 
termed the lower austral life zone, extending to some ex- 
tent into the upper austral zone. This fact, however, and 
the existence of this mosquito in a given locality, does 
not mean that there is any danger in such localities of 
yellow fever, unless one or more cases of the disease are 
brought into the locality and exposed in such a way that 
mosquitoes have the opportunity to suck their blood and 
fly away untrammelled to some healthy individual. MOSQUITOES AND YELLOW FEVER 
139 
Hon. John R. Procter, in a paper entitled “ Notes on 
the Yellow-fever Outbreak at Hickman, Ky., 1878,” pub- 
lished in bulletin of the Kentucky Geological Survey, No. 
1, 1879 (?), pp. 63-99, two maps, gave a most careful history 
of all of the cases of yellow fever which occurred at Hick- 
man in the summer of 1878, from which it appears that 
the causation of many of the cases which remained ob- 
scure is readily explainable on the theory of the transfer 
of the disease by mosquitoes. Mr. Procter (now Presi- 
dent of the United States Civil Service Commission) 
on learning of the thesis supported by the Army Yellow- 
fever Commission, was struck by the fact that the mos- 
quito theory explained away these doubtful cases, and 
called the writer’s attention to his publication. This is 
the only yellow-fever report which the writer has exam- 
ined carefully, but very likely many others have been 
published which should be critically examined from this 
point of view. Surely the detailed accounts of the older 
epidemics in this country, so carefully described in La 
Roche’s admirable monograph on yellow fever, do not, on 
cursory examination, offer any facts inconsistent with the 
adoption of the mosquito explanation of the spread of the 
dread disease. 
The importance of this discovery to Cuba and other 
tropical regions cannot be minimized. Word came to us, 
April 1st, from Havana, that for the first time in the history 
of that city the month of April began, in 1901, without a 
single case of yellow fever within the city limits. Much of 
this result is attributed to the admirable methods of san- 
itation introduced by our army soon after the occupation 140 
MOSQUITOES 
of the city. Some part of it must also be attributed to 
the excellent quarantine service under the charge of the 
United States Marine Hospital Service, but also, without 
doubt, much of the result must further be attributed to the 
hospital and barrack methods, and treatment of mosquito 
breeding-places carried on under the direction of the 
medical corps of the army. 
Mosquitoes and Filariasis. 
The first evidence scientifically obtained that mosqui- 
toes play a part in the spread of a disease was in the case 
of the parasitic worms of the genus Filaria, which are re- 
sponsible in Oriental tropical regions for the terrible 
disease known as elephantiasis. The adult worm lives in 
the skin of different parts of the body, lodged in the 
lymphatic vessels. The two sexes are found side by side, 
and are capable of living there a long time. They ob- 
struct at certain points the flow of the lymph. This ac- 
cumulates and dilates the vessels and the lymphatic 
spaces. This mechanical distention is accompanied by 
an irritation of the vessels and of the surrounding con- 
nective tissue. Thus, elephantiasis becomes established, 
which, as is generally known, manifests itself in very dif- 
ferent degrees and occupies different parts of the body, 
such as the arm, the leg, or the scrotum. 
The female Filaria enclosed in tlie lymphatic vessels 
is viviparous. The embryos to which she gives birth 
spread in the lymph and then with it into the blood, and 
it is in the blood that they are commonly observed. MOSQUITOES ANI) F1LARIASIS 
141 
They are found in abundance in the blood during the 
night or during sleep, but during the day, or, rather, 
while the patient is awake, they cannot be found. There 
seems to be no good explanation of this periodicity, nor 
is it absolutely exact, but it constitutes a very curious 
adaptation of the parasite to the nocturnal habits of the 
Fig. 36.—Cross Section of Head and Beak of Mosquito, showing Filarias 
entering Beak; enlarged. (Redrawn from British Medical Journal.) 
mosquito, which serves as an intermediary host. Having- 
more than twenty years ago proved this periodicity of 
the embryos, Dr. Patrick Manson had the happy thought 
that as mosquitoes bite men during sleep, perhaps they 
may be agents in the transmission of the disease, and his 
subsequent observations proved the correctness of this 
idea. The Filaria embryos, according to his observa- 142 
MOSQUITOES 
tions, sucked into the stomachs of mosquitoes, lose their 
hyaline envelope, work through the wall of the stomach 
and enter the muscles of the thorax, where they lodge 
between the muscle bundles, remaining there for two or 
three weeks, growing and taking on the character of the 
larva. This is as far as the evolution was for a long time 
observed, but upon it was based a theory by which the 
etiology of tilariasis was explained. This was, that the 
bodies of the mosquitoes falling in water, at death rap- 
idly disintegrated, liberating the parasites into the water, 
which when drunk by human beings carried the parasites 
once more into the human body. 
» Although plausible, it was difficult by this theory, as 
Blanchard has pointed out, to explain the constant pres- 
ence of the parasite in the lymphatics in the skin. How 
can the animal introduced into the intestinal tube make 
its way into the lymphatics of the arms and legs? It is 
difficult to suppose that it does this by going through the 
lymph vessels, which are provided with valves. Bancroft, 
of Australia, suggested that possibly the Filaria might be 
introduced into the blood of a healthy person by the bite 
of the same mosquito, assuming that the embryos in their 
penetration into the muscular part of the thorax might 
work into the beak. 
Through the researches of Bancroft, Manson, and Low, 
following this idea, it was discovered that up to the sev- 
enteenth day the larval Filarias in the mosquitoes are 
found exclusively in the thoracic muscles, but after that 
some of them begin to travel. They collect in the con- 
nective tissue in the anterior part of the thorax in front MOSQUITOES AND FILAR IAS IS 
143 
of the muscles. They are then about eighteen to twenty 
micromillimetres in diameter, and a little slenderer than 
those which remain in the muscles. By the twentieth 
day those remaining in the thorax have grown larger and 
have begun to break down the muscular tissue. Those 
which have migrated are found to have penetrated the 
neck, accumulating in the head, and penetrating into the 
beak. The question of transmission then becomes very 
much like that of the transmission of the malarial germs, 
and it seems reasonably sure that the Filaria is inocu- 
lated directly into the skin by the beak of the mosquito, 
and it is in the skin of man that the parasite accomplishes 
its last metamorphosis and becomes adult. In the skin 
they pair, and the embryos, issuing in the lymphatic 
spaces or vessels, are carried by the lymph into the blood- 
Thus the life round is complete. 
Tlic mosquito which is concerned in this work is not an 
Anopheles, as is the case with malaria, bnt a Cnlex. The 
one studied by Bancroft in Australia is one of the com- 
mon domestic Australian mosquitoes, Culex ciliaris 
Linn., which is possibly a synonym of Culexpipiens Linn. 
Other species may be involved, and, in fact, other biting- 
insects than mosquitoes, but these points are not yet 
thoroughly determined. VI 
Other Genera of North American Mosquitoes 
HAYING given a full consideration to the common 
mosquitoes of the genus Culex, which includes by 
far the majority of all of the mosquitoes which in- 
habit North America, and having paid special attention 
to the forms of the genus Anopheles, which comprises all 
the species which have been proved to carry the malarial 
germs, and having also told the story of the yellow-fever 
mosquito, there remain for brief consideration the mos- 
quitoes of the six additional genera known to occur in the 
United States. The structural peculiarities of these six 
genera are described in full in Chapter X., and since they 
are few in number of species, and since until recently all 
of them were unknown except in the adult condition, this 
consideration must necessarily be brief. 
Genus Psoropliora Desvoidy 
The insects of this genus are large mosquitoes, and 
only one species, Psorophora ciliata of Fabricius, inhabits 
the United States. In this insect the palpi in the male 
are longer than the proboscis, while in the female they 
are less than one-lialf as long as the proboscis. The 
144 OTHER GENERA OF MOSQUITOES 
145 
proboscis itself is straight. The most striking charac- 
teristic, however, is the presence of very peculiar erect 
scales on the legs. The hind legs especially are fur- 
Fig. 37.—Adult Female of Psorophora ciliata; enlarged. (Author’s 
illustration.) 
nished with large scales which are placed at right angles 
to the leg itself, and similar scales are present in smaller 
numbers upon the middle legs, and in very small num- 
bers upon the end of the thighs of the front legs. P. 146 
MOSQ TJITOES 
ciliata is a very large mosquito and is undoubtedly one 
of the forms known in the South as gallinippers. It is 
really yellowish in color, yet the general effect when one 
glances at it or sees it Hying is that it is very dark—al- 
Fig. 38.—Females of Psorophora ciliata at rest on side wall and ceiling ; 
enlarged. (Author’s illustration.) 
most black. The wings are not really spotted or dusky 
but the very numerous dark scales on the main veins 
make them appear dark. When seen in certain lights 
they are prismatic in their color effect. I have said that 
they are large. The length of the body of the female is 
about ten millimetres, but the length from the tip of the 
beak to the tip of the hind legs is nearly twice this. OTHER GENERA OF MOSQUITOES 
147 
This large and handsome mosquito * is a wide-spread 
species and is known to occur in Massachusetts, New 
Jersey, Pennsylvania, District of Columbia, Virginia, 
Connecticut, Illinois, Indiana, Florida, Louisiana, Arkan- 
sas, Nebraska, Texas, and California. It is, however, 
rare in its northern range, and in Massachusetts and 
New Jersey, for example, it is found only in low-lying 
Fig. 39.—Mule of Psorophora ciliata, from side ; enlarged. (Original.) 
regions. As a matter of fact, it seems to be really one 
of those species which is a true inhabitant of what is 
called the lower austral life zone, which comprises most 
of our Southern States. It may have a tropical range, 
but among the many mosquitoes which I have received 
from Mexico, Nicaragua, and Cuba, this species does not 
occur. Neither Psoropliora nor the next genus, Mega- 
* Many mosquitoes are really handsome, when seen under the lens, 
but few people will admit that creatures which they so heartily detest 
have any aesthetic value whatever. This is plainly to be seen in the case 
of snakes. MOSQUITOES 
148 
rliinus, have been studied by investigators working upon 
the transfer of blood-inhabiting parasitic germs by mos- 
quitoes, and I have urged that physicians and bacteriol- 
ogists in our Southern States pay some attention to them 
from this point of view. 
Nothing was known 
about the early stages of 
Psorophora until the end 
of August, 1900. In the 
early part of the summer 
(in June), a large series 
of living specimens was 
captured at St. Elmo, Va., 
by one of my assistants, 
Mr. F. C. Pratt, and we 
expected that we should 
be able to secure eggs 
without difficulty and to 
study the insect in its dif- 
ferent stages. The females 
were placed alive in large 
battery jars, under condi- 
tions which had repeatedly 
been successful with mosquitoes of the genera Cnlex and 
Anopheles, but no eggs were deposited. This brought 
me to the conclusion that either the confined specimens 
were not impregnated or that they had already deposited 
all their eggs, or that their breeding habits differ from 
those of other mosquitoes. On August 30th some very 
large mosquito larvae and pupae were received from Mr. 
Fig. 40.—Young Larva of Psoroph- 
ora ciliata; enlarged. (Author’s 
illustration.) OTHER GENERA OF MOSQUITOES 
149 
William P. Seal, of the Aquarium Supply Company, 11 
Delair, N. J. On examining them I felt sure that they 
Fig. 41. —Full-grown Larva and Pupa of Psorophora ciliatn, with en- 
larged parts ; enlarged. (Author’s illustration.) 
could be nothing less than the larvae and pupae of Psoro- 
phora ciliata. The first specimens received were in alco- 
hol, and Mr. Seal was informed of their probable identity, 150 
MOSQUITOES 
and urged to send on living specimens in water, and to en- 
deavor to rear the adult. It was then, however, unfor- 
tunately, too late. He wrote that during the summer a 
small creek and some earth ponds on his place became 
entirely dry, in consequence of which all fish in them 
died. Some time in August there was a sufficient rainfall 
to fill a few of the deepest places, which soon after be- 
came almost alive with mosquito larvae. These were used 
for fish-food, until it was noticed that they were develop- 
ing to the pupa stage, when coal oil was immediately 
poured on the water. It was while the coal oil was be- 
ing applied that the big larvae and pupae were first no- 
ticed. Mr. Seal had been a collecting naturalist for 
twenty-six years, supplying material for the aquarium 
and for biological research, and had discovered some low 
forms of life new to science, which were described by 
Leidy and Ryder, but in all his experience he had never 
seen such large mosquito larvae. 
On being assured of the novelty and importance of his 
observation, he promised to watch for the subsequent 
appearance of similar larvae, and on September 20th 
found other specimens which appeared after a rain which 
occurred on September 15th or a little before. Mr. 
Seal was able to distinguish between them and the 
Culex larva!, and wrote that they were very scarce—per- 
haps one of them to many thousands of the others. On 
September 25th additional larvae and pupae were sent 
in, and from these specimens the accompanying illustra- 
tions were made. 
Tlie larva is structurally of great interest. On com- OTHER GENERA OF MOSQUITOES 
151 
parison with larva of Culex, which it resembles more 
nearly than that of Anopheles, it will be seen that the 
breathing tube is longer; that the anal flaps are longer 
and more pointed, and the hair fringe on the under side 
of the last segment of the body is much longer and 
denser, while the mouth-parts are quite different. The 
jaws are sharply toothed, and very long, and are used in 
the mastication of food. Other mosquito larvae feed upon 
spores of algae and other small particles which appear to 
require no mastication, but this larva descends to the 
bottom of the water and has been noticed to grasp a bit 
of water-plant half an inch long and actually to chew it. ( 
The duration of the pupal stage was from four to five 
days, and the adult insects issued on September 27th and 
28tli. Young larvae were also found in this sending, and 
one of them is shown in Figure 40. 
The breeding-places in which these larvae were found 
were small depressions in the bed of a small stream, and 
similar hollows in certain small ponds, all of which were 
dry the greater part of the summer. After they first 
dried in the spring they were barren of fish and vegeta- 
tion. Mr. Seal is satisfied that the insect is rare in the 
vicinity of Philadelphia, and thinks that possibly he may 
have brought this species from the South, as he is in the 
habit of shipping large quantities of aquatic plants from 
the South, from January 4tli to about May lOtli of each 
year. He has a place some miles from Delair where he 
grows Cabomba. The plant is very dense, and the creek 
is full of fish, but in the water on top of the plant, which 
grows to the surface, are large numbers of mosquito 152 
mosquitoes 
larvae. They are out of sight and practically out of reach 
of the fish. 
The eggs of this interesting mosquito are yet to be 
found, and it will be most interesting to see in what re- 
spects they differ from the eggs of Culex and Anopheles. 
Genus Megarhinus Desvoidy. 
Another of the large mosquitoes which seem to be col- 
lectively known in the South as gallinippers (probably 
also some of the harmless crane-flies are so dubbed) 
belong to this genus. In fact there are two of them 
known in North America, namely Megarhinus hcemer- 
rhoidalis F. (Mexico and Cuba), and M. portoricensis 
Boeder (Mississippi). These mosquitoes also should be 
investigated by Southern observers in regard to their 
possible connection with malaria, or some other blood 
disease. They are readily distinguished from other mos- 
quitoes by the curved beak. The palpi in the male 
are as long as the proboscis, but are short in the female. 
The colors are bluish or greenish. 
Nothing1 is known of the life history of the mosquitoes 
of the genus Megarhinus, and some Southern observer has 
an admirable chance to add to the sum total of human 
knowledge by a series of careful observations on one of 
these forms. OTHER GENERA OF MOSQUITOES 
153 
Genus Aedes Meigen. 
The mosquitoes of this genus are minute forms, insignif- 
icant in color, and apparently rare. One species, Aedes 
fuscus Osten Sacken, has been found at Cambridge, Mass. 
Fig. 42.—Aedes fuscus, female ; enlarged. (Author’s illustration.) 
Aedes fuscus, according- to a recently published note by 
Dr. »T. D. Smith, has been reared by Mr. J. Turner Brake- 
ley at Hornerstown, N. J., from larvae found in the pitchers MOSQUITOES 
154 
of the pitclier-plant (>Sarracenia). The determination was 
made by Mr. C. W. Johnson, of Philadelphia, and is there- 
fore undoubtedly correct. 
Pig. 43.—Toxorhyncliites rutilus, female; enlarged. (Author’s 
illustration.) 
As pointed out in tlie synoptic tables in Chapter X. 
the palpi in both sexes are short, which distinguishes 
these little mosquitoes from other North American 
forms. OTHER GENERA OE MOSQUITOES 
155 
Stegomyia, Toxorhynchites, Uranotsenia and 
Concliyliastes. 
As will be pointed out and fully explained in Chapter 
X., these four generic names are here used for certain 
American mosquitoes for the first time. I am able to use 
them in this book through the great courtesy of Mr. F. Y. 
Theobald, of Wye, England, who has sent me proof sheets 
of his monograph of the mosquitoes of the world, now 
being published by the British Museum. Stegomyia 
includes, as has already been shown, the yellow-fever 
mosquito, S. fasciata, and it also includes the species 
mentioned in my previous writings as Culex signifer Co- 
quillett, and which has been captured in the District of 
Columbia and Virginia by Messrs. Coquillett, Barber, and 
Pratt. Toxorhynchites includes the species previously 
referred to as Megarhinus rutilus and which must now be 
known as Toxorhynchites rutilus. Uranotsenia includes the 
North American species previously known as Aedes sap- 
pirhinus. Concliyliastes includes two species formerly 
placed in the genus Culex and which must now be known 
as Concliyliastes musicus Say and Concliyliastes posticatus 
Wied. The former species has been taken in Pennsylva- 
nia, Virginia, District of Columbia, and Texas by Messrs. 
Johnson, Pratt, Thayer, and Barber. YTT 
Natural Enemies of Mosquitoes 
WHERE mosquitoes exist in rain-water buckets 
and barrels they are apt to have none or very few 
natural enemies. Tlieir principal enemies when 
in the aquatic larval and pupal stages are fishes and carniv- 
orous insects. Most carnivorous insects are rather slow 
breeders, and as a consequence they seldom deposit their 
eggs except in rather permanent pools, and naturally 
fish are found only in such places. There are, however, 
other enemies aside from these. Dr. C. W. Stiles informs 
me that during the summer of 1889, when working with 
C. H. Hurst, they collected at Leipsic a large number of 
mosquito larvae and pupae, and that many of them died in 
the laboratory. Upon opening one of the bodies, which 
was quite distended, he found a species of Mermis, one of 
the hair worms or hair snakes, coiled up in the body cav- 
ity. Examination of other dead larvae or pupae disclosed 
the fact that nearly every one was parasitized by the same 
species of Mermis. He showed the worms to Professor 
Rudolph Leuckart, who informed him that he had re- 
peatedly found the same Nematode in former years, and 
that he had observed that in years when mosquitoes were 
numerous the worm is very scarce. This led him to be- 
15G NATURAL ENEMIES OF MOSQUITOES 
157 
lieve that the parasite was a not unimportant factor in 
destroying mosquitoes near Leipsic. Later, Dr. Stiles 
found the same worm in mosquito larvae and pupae taken 
from other breeding-places, and it was quite noticeable 
that the parasitized insects were weaker in their move- 
ments than those that were not infected with the worm. 
In the next summer (1890) he again looked for the worm, 
but found none, and it appeared to him that mosquitoes 
were more abundant that year than in 1889. 
Dr. Stiles also informs me that a Sporozoan of the 
genus Glugea is referred to as parasitic in mosquitoes, but 
that Labbe, in his recent monograph of the Sporozoa, 
does not give Culex in his list of hosts. Dr. Stiles does 
not recall who found this parasite, nor does he know 
whether it is of any particular economic importance. 
By far the most effective natural enemies of mosquito 
larva) and pupae are fisli. Almost all of the small carni- 
vorous fish which inhabit swamp pools and still water 
will feed upon mosquito larvae. Nearly all of the minnows, 
especially those forms known as top-minnows, of the gen- 
era Fundulus and Gambusia, feed abundantly upon in- 
sects found near the surface of canals, slow streams, mill- 
ponds, and other similar places, and, although not at all 
specific in their choice of the early stages of the mosqui- 
toes, eat them perhaps with even more avidity than other 
aquatic insects, especially such as are liard-shelled. 
Then, too, the voracious little creatures known as stickle- 
backs, and especially the forms known as Gasterosteus acn- 
halm and G. bispinosus have this beneficial habit. Stickle- 
backs, however, are by no means confined to insects for 158 
MOSQUITOES 
food, but will feed upon other animals, including good- 
sized tadpoles. Anyone who has attempted to keep tad- 
poles and sticklebacks in the same aquarium will realize 
the truth of this statement. I once kept a large sized 
tadpole in the same aquarium with a stickleback, which 
it exceeded at least five times in size, and its personal 
beauty was soon sadly damaged by the fact that the 
stickleback subsisted upon meals taken from the edge of 
the tadpole’s tail. In his previously published bulletin 
Fig. 44.—Stickleback (Gasterosteus acvleatus); somewhat enlarged. 
(After Jordan and Evermann.) 
on mosquitoes tlie writer recommended sticklebacks for 
introduction into fisliless ponds to destroy mosquito lar- 
vae, but Mr. W. P. Seal, of the Aquarium Supply Com- 
pany of Delair, N. J., recommends the so-called top-min- 
nows of the genus Gambusia, common in the brackish 
waters of the Chesapeake system and southward. He 
says fliese are the only fish he knows which will kill No- 
tonecta (the water-boatman), but they do this only when 
other food is scarce, and when the bugs are small. The fish 
vary in size from an inch for the males, to about one and 
three-quarter inches for the females. They live equally NATURAL ENE3IIES OF MOSQUITOES 
161 
to swim, “ yet they seemed happy.” As elsewhere stated, 
they are viviparous, and l)r. Veazie says that a little 
female will expel large numbers of the young at one time, 
and that they can be raised in almost anything that holds 
water. He has seen them swimming around under a layer 
of ice, as unconcerned and active as they would have been 
on a hot July or August day. 
I have been thus explicit in referring to these fish, and 
have illustrated the best forms, for the reason that a very 
practical use can be made of them. It was stated a num- 
ber of years ago in Insect Life, that mosquitoes were at 
one time very abundant on the Riviera in South Europe, 
and that one of the English residents found that they 
bred abundantly in the water tanks, and introduced carp 
into the tanks for the purpose of destroying the larvae. 
It is said that this was done with success, but the well- 
known food-habits of the carp seem to indicate that there 
is something wrong with the story. If top-minnows or 
sticklebacks had been introduced, however, the story 
would have been perfectly credible, and it points to the 
practical use of fish under many conditions. Some years 
ago Mr. C. H. Russell, of Bridgeport, Conn., described a 
case in which a very high tide broke away a dike and 
flooded the salt meadows of Stratford, a small town on 
the north side of Long Island Sound. The receding tide 
left two small lakes nearly side by side, and of the same 
size. In one lake the tide left a dozen or more small fish, 
while the other was fishless. An examination by Mr. 
Russell in the summer of 1891, showed that while the 
fishless lake contained tens of thousands of mosquito 162 
MOSQUITOES 
lame, that containing the fish had no larvae. Mr. E. A. 
Schwarz informs me that in Beeville, Tex., a little fish 
which is known locally as a perch is put into rain-water 
tanks for this express purpose. 
There occur on many large estates in the northeast and 
elsewhere, ponds which are used for watering stock. 
These are sometimes artificial ponds built with rock 
bottoms to prevent the exit of the water. They cannot 
be drained, and on account of their purpose they cannot 
be treated with kerosene. Into such ponds should be 
introduced a plentiful supply of top-minnows or some 
other voracious mosquito-eating fish. 
Iii a later conversation with Mr. Seal, lie told me that the 
top-minnow was suggested because it is a top-feeder, and 
being very small and slender, it penetrates to the remot- 
est shallows of the Avaters which it may inhabit, especially 
where plants abound and where larvae of mosquitoes are 
sure to be found. On second thought, he was inclined to 
think, however, that for general purposes the common 
little flat sunfish, or “ pumpkin-seed ” as it is sometimes 
called, would be a good fish to introduce into fisliless 
ponds. It grows much larger, of course, but is very pro- 
lific, and the young do not make a very great growth in a 
year, so that the young of each year remain compara- 
tively small, say from tliree-fourtlis of an inch to a half- 
inch, until the young of the following year would be 
ready for business, which would be by July 1st. The top- 
minnow, he says, being a soft-rayed fish, becomes the 
easy prey of larger fishes introduced into the same 
waters, but the sunfish, being protected by spine-rayed NATURAL ENEMIES OF MOSQUITOES 
163 
fins, enjoys greater freedom from molestation. The sun- 
fish, he says, abounds in every pond and stream where 
fish are plentiful, excepting cold mountain-streams. 
Every aquarium dealer in any large city will be able to 
supply the common sunfish. Mr. Beal further notes that 
the common sunfish is the most voracious of the smaller 
fishes. It has a larger mouth than the top-minnow 
Fig. 47.—Common Sunfisli or “Pumpkin-seed” ; reduced. (After Jor- 
dan and Evermann.) 
and is wholly carnivorous, whereas the top-minnow is 
omnivorous. On mature consideration, he gives prefer- 
ence to the sunfish as most completely filling the bill. 
There are other aquatic vertebrates, besides fish, 
which destroy mosquito larvae. I am not sure that tad- 
poles eat them—there seems to be some doubt on that 
point—but my friend, Mr. Albert Koebele, informs me 
that he imported into Hawaii from California a large 164 
MOSQUITOES 
number of the western salamander (Diemyctylus torosus 
Esch.) which were liberated in the upper part of the 
Makiki stream in the hope of reducing the large number 
of mosquitoes breeding everywhere in small pools and 
taro fields. He kept two of these salamanders for sev- 
eral weeks in an open tank, and they devoured, and kept 
the water free from, the mosquito larvae that bred there. 
While hundreds of the neAvly hatched mosquito larvae 
could always be observed, none of them ever reached full 
growth. Mr. Koebele says, “ It is to be greatly desired 
that this valuable batrachian will increase to such num- 
bers as to be able to help us keep in check the most 
troublesome insect on these islands.” 
Then there are many predatory insects which feed upon 
mosquitoes. The late Dr. It. H. Lamborn, of New York 
and Philadelphia, was so impressed with the voracity 
of dragon-flies that he offered a series of prizes for the 
three best essays regarding the methods of destroy- 
ing mosquitoes and house-flies, especially designating 
the dragon-fly for careful investigation. The prizes were 
awarded and the successful essays were published in an 
entertaining volume entitled “ Dragon-flies vs. Mosqui- 
toes. The Lamborn Prize Essays.” None of the essays 
were able to solve the problem of the practical breeding 
on a large scale of dragon-flies for mosquito extermina- 
tion, and, in fact, the insect enemies of the mosquitoes 
cannot be practically handled. Dragon-flies as larvae 
feed upon mosquito larvae, just as they feed upon all 
other aquatic insects and even upon small fish. As 
winged adults they capture mosquitoes on the wing, just NATURAL ENEMIES OF MOSQUITOES 
165 
as they capture other insects on the wing. The same 
may be said of other predatory aquatic insects. Some of 
the aquatic beetle larvae and some of the predatory water- 
bugs undoubtedly destroy hundreds of mosquitoes. Any 
stagnant pool, when carefully watched, will be found to 
swarm with predatory animal life. From such a pool I 
once took a half gallon of water which was teeming with 
aquatic insects, including hundreds of mosquito larvae. 
Among these insects there were three water-beetle larvae 
of the family Hydropliilidae, and in the course of a week 
these three larvae practically devoured all of the other 
animal life in the jar. 
Tlie adult mosquito also lias its natural enemies. We 
liave already mentioned tlie dragon-flies, and many night- 
flying birds, such as night-hawks and whippoorwills, 
destroy them on the wing ; and bats, of course, feed upon 
them. An observation is on record by the late Prof. F. 
L. Harvey, in which he states that he found six hundred 
mosquitoes in the crop of a single night-hawk. In No- 
vember, 1900, Mr. E. P. Salmon, of Beloit, Wis., wrote 
me, “ There is a parasite, a little red louse, which attacks 
the mosquitoes on Madeline Island a few weeks after 
their appearance in June, and from the time this little 
red louse shows itself on the mosquito under the mosqui- 
to’s wings, the mosquito begins to lose his strength. 
After a few weeks, along toward the end of July, the 
mosquito ceases to be very troublesome and seems to be 
fighting with his parasite for his life.” This parasite is 
probably one of the little red mites which are found 
upon flies, and particularly upon the common house-fly. 1G6 
MOSQUITOES 
The mosquito being an aquatic insect, the mite observed 
by Mr. Salmon may be one of the little water-mites of 
the family Hydrachnidae, but the mosquito issues from 
its pupa so rapidly that this is hardly likely. It is more 
likely to be one of the Trombidiidae, the young of which 
may crawl upon the mosquito when it is at rest upon the 
plants. 
Some observations upon the natural enemies of the 
malarial mosquitoes of the genus Anopheles have been 
made by Dr. C. W. Daniels in East Africa (“Reports to 
the Malaria Committee of the Royal Society,” December 
31,1900). He says that fish, and especially young fry and 
small fishes, will speedily destroy the mosquito larvae, 
but in spite of this, Anopheles larvae are often found in 
pools, rivers, etc., where fish are abundant, and pupae and 
mature larvae among them. This is seen in open pools 
as well as in the grass-grown rivers. He also says that 
tadpoles do not attack the larvae even in captivity, and 
goes on to say that larvae of Coleoptera and dragon-flies, 
often found in numbers in water with abundant Anoph- 
eles larvae, even in captivity do not seem to devour them. 
In ponds where there are large-leafed water-plants, 
mosquitoes frequently escape the attacks of fish, and 
many more of their natural enemies, by holding to the 
water-surface, especially above partly submerged leaves. 
This is especially the case with Anopheles larvae, which 
remain quite at the surface during the best part of their 
existence VIII 
Remedies Against ATosquitoes 
AFTER a number of years’ experience in fighting 
mosquitoes, the present writer has come to the 
conclusion that there is no reason why any com- 
munity should submit to the mosquito plague. At first 
he only went so far as to state that there are many places 
where the source of the mosquito supply is circumscribed 
and limited, and easily handled, and that in such places, 
with a comparatively slight effort and small expense, 
mosquitoes could be controlled. As the work went on 
and as experiments were tried on a gradually increasing 
scale, it became more and more obvious that any neigh- 
borhood, if it cares to take the trouble and go to the ex- 
pense, may place its mosquito denizens hors du combat. 
But with mosquito work, just as with so many other pub- 
lic measures, what is everybody’s business is nobody’s 
business, and the result is that in many localities every- 
one submits to the mosquito evil. In some instances, in- 
dividual effort is all that is necessary; in others, united 
action on the part of the residents of a given neighbor- 
hood or a given community is needed, and, as will be 
later shown, there are still other measures which should 
167 168 
MOSQUITOES 
be handled by still larger organizations—even by States. 
Mr. Matlieson’s clever phrase, referred to in the intro- 
duction to this book, “ There is no more reason why peo- 
ple should suffer from mosquitoes than that they should 
suffer from smallpox,” is not an over-statement; and that 
the effort should be made when it promises success is 
so self-evident that it only requires a few enthusiastic 
and enlightened individuals in a community to convince 
everyone of the desirability of an organized effort. 
Setting- aside the question of yellow fever, which only 
at intervals concerns even the States along- the Gulf of 
Mexico, and is of vital and constant importance only in 
tropical regions, a mere passing thought shows the eco- 
nomic loss to a neighborhood in the prevalence of ma- 
laria. While the actual death-rate may not be high, the 
number of persons incapacitated for their full share of 
work is always great. Families suffer in one way or an- 
other, and the community, when the matter is considered 
in a broad way, is a great loser. Aside, too, from ma- 
laria, it is perfectly obvious that a mosquito-ridden 
neighborhood is not a desirable place of residence. The 
very fact of the abundance of mosquitoes keeps real 
estate values at a depressed point. I know of one case 
where a stretch of land near a large body of water af- 
forded many excellent cottage and villa sites, but mos- 
quitoes were so numerous that even domestic animals 
could not be kept in a healthy condition, and the sole 
population consisted of a few smoke-dried fishermen and 
their dogs. In this locality, by enterprising work on the 
part of one man, who organized a company for the pur- REMEDIES AGAINST MOSQUITOES 
169 
pose, the land was bought, the mosquito-breeding places 
were practically abolished, summer residences were built, 
and the company realized many thousands of dollars in 
the course of two years. There are, within a hundred 
miles of New York City, for example, hundreds of beau- 
tifully situated localities which are not utilized to their 
full possibilities largely on account of the prevalence of 
mosquitoes. There are many small towns which are un- 
desirable for summer residence on account of the abun- 
dance of mosquitoes, though in all other respects their 
qualifications for this purpose are perfect. 
Aside from the main questions of health and of the 
value of land, come the other subsidiary questions of com- 
fort, and of the unnecessary expense of screening houses 
with the thoroughness necessary in many localities, which, 
when considered in bulk, become important. It seems 
then evident that it would be a positive economy for a 
community to spend, if necessary, even a large sum of 
money in attempting mosquito-extermination. In very 
many cases, however, a small sum will suffice, provided 
it is administered with intelligence. 
Dr. C. Fermi, after giving1 an account before tlie Medico- 
physical Society of the University of Sassari, March 23, 
1900, of his efforts to free the town from mosquitoes, esti- 
mated the expense of freeing a town of 50,000 inhabitants 
at from $200 to $300. This sum seems extremely small, 
even with the low price of labor over there, but in the 
case of Sassari the mosquito-supply was local, and the 
insects bred almost entirely in household tanks and water 
receptacles. It is with large marsli-areas or numerous 170 
MOSQUITOES 
ponds in neighboring woods, and especially with the high 
brackish sea-coast marshes, that the expense would be- 
come very great. 
The consideration of the question of remedies may 
most conveniently be divided into the following main 
categories: (1) Remedial work against the early stages ; 
(2) Remedial work against the adults. 
Remedial Work Against the Early Stages. 
In considering the question of remedies against the 
early stages, we again find it most convenient to sub- 
divide the subject as follows: (1) The treatment of 
breeding-places with insecticides ; (2) The abolition of 
breeding-places by drainage, and (3) The introduction of 
natural enemies into breeding-pools, which for any rea- 
son it may be undesirable to drain, or to treat with oil. 
Before undertaking- work against tlie early stages of 
mosquitoes in any given neighborhood, it becomes neces- 
sary to make a thorough survey of the immediate sur- 
roundings, and to learn with great accuracy all of the 
places in which mosquitoes are breeding or may breed. 
In the section entitled “ Queer Places in which Mosqui- 
toes Breed ” (Chapter I.) an effort has been made to cover 
the ground rather thoroughly as an indication of what 
must be looked for. All accidental receptacles for stand- 
ing water must be emptied and must be kept emptied; 
waste ground in the vicinity must be thoroughly ex- 
amined, in order to find whether there are hollows in 
which rain-water accumulates or whether there are broken REMEDIES AGAINST MOSQUITOES 
171 
bottles, empty cans, or discarded vessels of any kind. 
About houses, the greatest care must be taken to examine 
every possible spot where still water may occur ; cisterns 
must be covered tightly, with, however, a sufficient aper- 
ture covered with wire gauze to admit of a plentiful aera- 
tion of the water; rain-water barrels should be either 
covered or treated with kerosene. In the surrounding 
ground every permanent pool and every swamp-area 
should be charted and the method of treatment determined 
upon; permanent pools not used for watering stock 
should be treated with kerosene; swamp-areas should 
be drained; and small depressions should lie filled with 
earth. All such work must be thorough and practically 
perfect, else it is hardly worth while to undertake it. 
The Use of Kerosene on Breeding Pools. 
As long ago as 1812, the writer of a work published in 
London, entitled, “Omniana or Horae Otiosiores,” sug- 
gested that by pouring oil upon water the number of 
mosquitoes may be diminished. Delboeuf, in the Revue 
Scientifique, 1895, says that he used kerosene in this way 
fifty years before. H. E. Weed, in 1895, stated that in the 
French quarter of New Orleans it has been a common 
practice for many years to place kerosene in the water 
tanks to lessen the number of mosquitoes in a given 
locality. Suggestions as to the use of kerosene were 
made by Mrs. Aaron, and by Beutennhiller, in the Lam- 
born Prize Essays, “ Dragon-flies versus Mosquitoes ” (D. 
Appleton & Co., 1890). In 1867 the present writer used 172 
MOSQUITOES 
kerosene in a watering trough at Ithaca, N. Y., and found 
that mosquito larvae were killed by it, and in 1892 con- 
ducted an experiment upon a larger scale in the Catskill 
Mountains, indicating the quantity of kerosene necessary 
for a given water-surface and showing that adult mosqui- 
toes are captured by a kerosene film ; that is to say, they 
alight on the surface of the water in an attempt to de- 
posit eggs and are destroyed by the kerosene before the 
eggs are laid. A full account of this last experiment was 
published in Insect Life, vol. ii., 1892, and, since it at- 
tracted considerable notice in newspapers, additional ex- 
periments by others upon a larger or smaller scale were 
speedily made. Mr. H. E. Weed rid the college campus 
of the Mississippi Agricultural College of mosquitoes by 
the treatment with kerosene of eleven large water-tanks. 
Dr. John 13. Smith recorded in Insect Life (vol. vi). suc- 
cess with this remedy in two cases on Long Island. Pro- 
fessor Y. L. Kellogg conducted a similar series of experi- 
ments upon the campus of Stanford University, California, 
in which cases post-holes filled with surface water were 
giving out large numbers of mosquitoes, but when a little 
kerosene was poured into each hole the mosquito plague 
was almost immediately alleviated. Rev. John D. Long, 
at Oak Island Beach, Long Island Sound, and Mr. W. R. 
Hopson, near Stratford, Conn., conducted large-scale ex- 
periments with good results. Mr. R. M. Reese, in Balti- 
more, treated open sewers with kerosene with excellent 
results. A little later (1898), Mr. W. C. Kerr, on Staten 
Island, did some large-scale kerosene work upon ponds 
and swamps, which resulted most satisfactorily. In 1897 REMEDIES AGAINST MOSQUITOES 
173 
Mr. M. J. W ightman oiled brackish marshes at an Atlantic 
coast resort for a radius of about half a mile, reducing 
the mosquitoes to innoxious numbers for an entire sea- 
son. Dr. St. George Gray, of St. Lucia, British Wrest 
Indies, used kerosene in his well and in water-jars in his 
yard with excellent result. 
All of this work was done before the malaria discover- 
ies directed the attention of European observers especi- 
ally to the question of mosquito control. In the early 
work of the Italian investigators the use of kerosene was 
rather discredited, one of the reasons adduced being that 
although kerosene is abundant and cheap in America, it 
was not known to the Italians that it was extensively used 
in this country—a pretty poor reason, but still, more or 
less effective over there. Even Major Ross, the English 
expert, seemed at first rather skeptical as to the value of 
kerosene, but returned from his West African expedition 
fully convinced of its value (Giles, 1900, pp. 76, 77), and 
since that time the use of petroleum oils has gradually 
become the standard treatment for mosquito-breeding 
pools. For example, Fermi and Lumbao, the Italian in- 
vestigators, think that one man, with one day’s teaching, 
could rid a good-sized city very largely of mosquitoes by 
repeating ten to twelve times, through a summer of seven 
months, the application of petroleum to the breeding- 
places. Mr. W. J. Matheson, in the summer of 1900, 
attained very successful results by treating an area of 
several square miles on the north shore of Long Island 
with kerosene, combined with certain drainage work. 
The army regulations in Cuba provide for the treatment 174 
MOSQUITOES 
of breeding-places witli kerosene, and the results are re- 
ported to have been admirable. The city of Winchester, 
Va., during the summer of 1900, was treated with kerosene, 
under an ordinance of the city council, with such good 
results that in the spring of 1901 the city council passed 
a further regulation providing a penalty for the 11011-treat- 
ment of breeding-places. This instance is one of such 
wide-spread interest that the ordinances of 1900 and 1901 
are printed herewith, together with a letter received in 
October, 1900, from the mayor of the city. 
[First Circular, 1000. j 
PREVENT THE MOSQUITO. 
The City Council has passed the following Ordinance : 
1. Be it ordained that on or before March 25, 1900, and at least 
once each month thereafter until November 1, 1900, each owner 
or occupier of a house or lot in the city, shall put into every pool 
or sink which is open, or from which there is any opening or out- 
let, kerosene oil at the rate of one ounce for fifteen square feet of 
surface of said pool or sink, and that quantity for any surface less 
than fifteen square feet. 
2. And be it further ordained that one-lialf an ounce of kero- 
sene oil shall during the same time be put in every open barrel or 
hogshead kept for the purpose of collecting rain-water ; and 
water shall be taken from such barrel or hogshead by a spigot of 
wood or metal placed as near as convenient to the bottom of said 
barrel or hogshead. 
3. It shall be the duty of the police, by proper inspection, to 
see to the enforcement of this ordinance, and to supply to persons 
unable to procure them the necessary oil and spigots. REMEDIES AGAINST MOSQUITOES 
175 
I am assured on the highest authority that if this plan is care- 
fully and pei'sistently carried out, it will after awhile result in 
entirely preventing the mosquito, whereas here its existence has 
not long been established and is wholly due to local causes. 
But the failure of a few to apply the oil on their premises will 
defeat all efforts to get rid of this dreadful pest. An ounce of 
oil will about fill an ordinary teacup ; smaller quantities wi 11 
suffice for spaces less than fifteen feet square ; a tablespoonful is 
enough for an ordinary rain-barrel ; evei*y little pool, however, 
must have its portion of oil, and the oil must always be renewed 
when washed away by rain, and this is especially necessary for 
rain-barrels. In any event the oil must be i-enewed at least once 
a month. 
I invite the cordial co-operation of all good citizens, 
R. T. Barton, Mayor. 
FIGHT THE MOSQUITO. 
[Second Circular, 1000. j 
The efforts made by our citizens since March 25th, in obedi- 
ence to the ordinance of the Common Council, to prevent the 
development of the mosquito during this season, seem to have 
resulted in most encoui-aging success. It is yet too early to de- 
termine to what extent we have destroyed this pest, but there 
can be no doubt of its having been done to a very large extent. 
Every experiment carefully watched has demonstrated the effi- 
cacy of coal-oil applications and all that seems to be needed is 
to continue diligently the use of oil, but unless we do, all that 
we have done in the past will amount to nothing. It is not 
necessary to repeat suggestions heretofore published, lest, how- 
ever, some may have forgotten its terms, I append hereto a copy 
of the ordinance : 
R. T. Barton, Mayor, 176 
MOSQUITOES 
[Third Circular, 1900] 
CONTINUE TO FIGHT THE MOSQUITO. 
Although it is greatly diminished in numbers, even to the ex- 
tent of being no longer a serious trouble, yet by its unmistakable 
presence here and there the mosquito has made it evident that 
all of them are not dead. The success of the plan has far exceed- 
ed our expectations for the first season. All that is needed now 
to eliminate them as a feature of this community is to keep up 
the fight diligently until November, when we will take a rest 
until the next season. The chances are that what we will do 
next year will be mainly as a wise precaution against the possi- 
ble recurrence of the pest. That you may not forget the history 
of this insect and why it is possible to destroy them by the use 
of oil, I repeat a publication made once before. 
July 17, 1900. 
R. T. Barton, Mayor. 
How the Mosquito is Bred. 
Its germinal period is often about twenty-five days from the 
laying of the mosquito-egg to the full maturity of the insect, of 
which time only about three days are spent in the eggs. The 
average germinal period is about three weeks. I say ‘ ‘ about ” 
for the time is not always exactly the same, depending, as it 
does, very much upon the condition of the weather and water. 
The female lays about 300 eggs at a time in some pond, cistern, 
tank, cesspool, rain-barrel, or any quiet pool of water. The 
eggs are glued together in the shape of a pretty little boat and 
left to float and hatch. They retain this “wiggler” condition 
for from five to fifteen days, remaining all the time in the water 
but changing their skins several times. REMEDIES AGAINST MOSQUITOES 
177 
After from five to fifteen days the larva; become pupae or “tum- 
blers,” so called from their bobbing up and down or turning 
over in the water. After five to fifteen days of pupa-hood the 
skin opens at the back and the mosquito comes out. It dries its 
wings and is then ready for business on dry land. The female is 
the business member of the house, and it is she who sings and 
sucks the whole night through. 
The natural food of the mosquito is vegetation, and with this 
the male contents himself. It is the female alone that develops 
a carnivorous appetite. The life of the mosquito is short, but 
from the later hatchings of the fall a great number live over 
winter in garrets, cellars, etc., for the cold does not kill them. 
In early spring the female begins to lay her eggs, and as she 
lays about 300 in each bunch, the rate of increase is prodigious. 
Hence the importance of anointing with oil all pools of water. 
When the female comes to lay her eggs she will desist, and lay- 
ing them on some twig or leaf, they will perish. If she alights on 
the oil-anointed water she perishes and her eggs perish with her. 
If the eggs have been laid before the oil is put in the water and 
the insects are in either larva or pupa state when the oil is put 
in, it will destroy them. 
The most important time then to fight this insect is just at 
this season before they have multiplied, as they will do in a few 
weeks if left alone. Since, however, the mosquito goes on lay- 
ing and hatching until about November, it is necessary to fight 
it all the season through, perhaps several seasons through. 178 
MOSQUITOES 
[Letter from the Mayor.] 
Dr. L. O. Howard, 
Winchester, Va., October 5, 1900. 
Entomological Bureau Agricultural Dep't, 
Washington, I). C. 
Dear Sir : I have for some time had it in mind to write you 
an account of our war against the mosquitoes in this town ; 
thinking that inasmuch as we made the fight along the line of 
your published suggestions you would be interested in learning 
the extent of our success. 
Until about ten years ago a mosquito in Winchester was as rare 
as a horse in Venice. About ten years ago, the increase in their 
numbers began to be apparent, but it was not until five or six 
years ago that they became a positive annoyance. Their advent 
here was attributed to a line of parlor cars established as anight 
train on the B. & 0. It. It., running from Camden Station, Balti- 
more, in the summer-time. This may have added to the num- 
ber, for recent investigation has shown that the returning empty 
cattle cars, which stand for a time at the stock-yards in Balti- 
more, bring great numbers of mosquitoes all along this mountain 
country wherever the trains run. 
My own opinion, however, is that we owe the great increase to 
the scanty original stock here, which was enabled vastly to 
multiply its numbers because of a new and much extended sys- 
tem of water-works, which led to the greatly increased use of 
bath-tubs and water-closets ; and having no system of sewerage, 
the excessive use and waste of water stands in numerous cess- 
pools, which are the prolific breeding-places of the mosquito. 
Then, too, there is a stream of water, arched over where the streets 
cross, which, after heavy rains and when the regular stream has 
subsided to its ordinary dimensions, consists of a large number REMEDIES AGAINST MOSQUITOES 
179 
of still pools, which are tine for the egg-hatching and larva and 
pupa raising by the mosquito. The arches over this stream 1 
found last spring to have been the favorite hibernating places of 
the insect, and before they had fully time to wake up and go to 
business, I had millions of them destroyed by sprinkling with 
coal tar. 
Last summer my attention was called to your suggestions about 
the use of oil, by my brother-in-law, Dr. R. W. Baker, of your 
city. At my request he called on you and procured some of the 
literature issued by you on the subject. 1 determined that 1 
would urge the people here to try the experiment. In October, 
1899, the mayor having died, I was unexpectedly chosen in his 
place, and I then thought of trying to make the matter one for 
municipal and methodical action. I therefore induced the Com- 
mon Council to pass an ordinance, a copy of which I enclose to 
you. 
My proposition was greeted by the papers and by the com- 
munity generally with much merriment, and 1 was the subject of 
some very sharp ridicule from the press at home and abroad. 
The ordinance, as you will see, was without penalty, and the 
course designed to be pursued by me was intended to be per- 
suasive and not coercive. Early in the spring (March) I dis- 
covered the mosquitoes buzzing out from a pile of plank when the 
snow was six inches deep, and the first reports of the police who 
undertook to anoint the run and all public pools, was that mill- 
ions of them were found adhering to the arches, and the oil-cans 
when brought out from use under the arches and in the pools 
were covered with the dead insects. 
I issued to the people small leaflets, giving an account of the 
habits and gestation period of the mosquito, and urging the peo- 
ple to obey the ordinance and join me in a relentless fight against 
the insect. I also asked many persons to make experiments and 
report their success to me. I was soon overwhelmed with re- 180 
MOSQUITOES 
ports and all of them of the most favorable character. One 
entirely reliable gentleman reported to me that within five 
minutes after he had anointed a rain-barrel, seventy-five mos- 
quitoes (presumably females) came to the barrel and seventy- 
three of them perished, while the other three made haste to 
escape. In one case, a lady reported to me that she took nearly 
a pint of the dead insects from a hogshead the morning after 
putting the oil in it. These and reports like them greatly 
encouraged my efforts, and soon the oil was in almost universal 
use and the town smelled like a Standard Oil tank. I continued 
from time to time to issue the leaflets, and followed them up with a 
police inspection. The result has been a wonderful success. The 
plague, while by no means entirely abated, has been decreased to 
a marked degree. In many parts of the town, the nets used so 
constantly heretofore have been thrown away, and there are no 
mosquitoes at all. In other parts, while their numbers are 
lessened, they still continue to be a nuisance. This difference is 
doubtless due to the neglect of some persons in the particular 
neighborhood to use the oil ; and also, no doubt, to peculiar 
facilities afforded for mosquito breeding in some parts of the 
town more than in others. 1 observed a decided increase in the 
number in the latter part of August and in the month of Sep- 
tember. 
Just now we are greatly increasing our efforts toward their 
destruction, so as, if possible, to destroy the crop that would 
hibernate, and thus reduce the number of breeders to live over to 
spring. 
There can be no doubt about the success of the scheme. All 
that is needed is persistent, unremitting application of the oil to 
all pools, sinks, water-closets, old cisterns, etc., etc., and another 
season we expect to have an ordinance with a penalty attached 
and to enforce the oil anointing even more systematically than 
has been done this year. REMEDIES AGAINST MOSQUITOES 
181 
To your suggestions we are indebted for what promises to be 
complete relief from this pest, and for an exemption during the 
past summer to an extent that has added very much to the pleas- 
ure and to the profit of living in this town. I thank you very 
much in my own name, and in that of all of our people, for the 
good that your wise and practical investigations have done. 
Yours very truly, 
R. T. Barton. 
[First Circular, 1901. ] 
MOSQUITO CAMPAIGN OF 1901. 
The admirable results obtained during the last year from fight- 
ing the mosquitoes seem to assure us that one more campaign 
will end them for Winchester, and restore conditions existing a 
few years ago when this insect was unknown here. The present 
ordinance is more stringent than that of last year and provides a 
penalty for its disobedience. Still, it is only the very few who 
are driven by the fear of the law. Its successful enforcement de- 
pends after all upon a cheerful compliance by the good and law- 
abiding citizens. I publish the ordinance now, for your informa- 
tion, calling especial attention to the fact that the use of the oil 
must begin on March 15th ; much earlier than last year, as we 
learned from observation that we did not begin early enough 
then. The oil must be renewed at least every three weeks, and 
1 suggest, so that it may not be overlooked, that the first and fif 
teenth days of each month be “ oil days ” in your calendar. 
I hope that it will not be necessary either to appoint an in- 
spector or to impose a penalty for disobedience of the ordi- 
nance. 
R. T. Barton, Mayor. 182 
MOSQUITOES 
An Ordinance to provide a method for the destruction and pre- 
vention of the mosquito in the city of W inchester. 
Be it ordained by the Common Council : 
1. That on or before March 15, 1901, and at least every three 
weeks thereafter, until November 15, 1901, there shall be depos- 
ited in every open pool or sink, or all from which there is any open- 
ing or outlet, and upon the surface of every barrel or hogshead 
kept for collecting rain-water ; and upon every receptacle of any 
sort in which water is allowed to stand for as much as twenty- 
four hours on every lot in the city of Winchester ; and on every 
open pool of any sort in every street or square and along the 
bed or course of the town run, in said city of Winchester ; kero- 
sene oil, at the rate of one ounce for each fifteen square feet, and 
a proportionate quantity for any less surface. 
2. It shall be the duty of every owner or occupier of any house 
or lot in the city to make the deposits of oil as provided in this 
ordinance; and in the case of barrels, hogsheads, or other recep- 
tacle kept on the premises for the collection of rain-water, water 
shall be drawn from said receptacle by a spigot of wood or metal 
placed as near as convenient to the bottom of said receptacle. 
3. It shall be the duty of the police, under the instructions of 
the mayor, to see to the enforcement of this ordinance, and to 
supply persons unable to secure them with the necessary oil and 
spigots. 
4. The mayor shall have authority, if in his judgment the oc- 
casion requires it, to appoint an inspector of pools, sinks, etc., 
removable at the pleasure of the mayor, and whose duty it shall 
be to report any failure to comply with the provisions of this 
ordinance; and who, under the instructions of the mayor, shall 
have authority to enter any premises, and himself make the re- 
quired deposit of oil. The pay of said inspector shall not exceed 
$5 a week, to be paid by the treasurer out of the public funds. 
5. Every owner or occupier of a lot who shall fail to comply REMEDIES AGAINST MOSQUITOES 
183 
with, or shall offend against the provisions of this ordinance, 
shall for each offence or failure be liable, upon conviction there- 
of, to pay a fine of one dollar, which shall be recoverable as pro- 
vided by section 9 of the General Ordinances of the City of Win- 
chester. 
6. The sum of $25 is hereby appropriated for the enforcement 
of this ordinance, in addition to the compensation of the in- 
spector, in case one shall be appointed. 
I venture to predict that these papers will eventually 
possess an historical value, since without doubt other 
communities will soon follow the example set by this en- 
terprising Virginian town, and that mosquito warfare on 
these or somewhat similar lines will before long become 
a part of the duty of very many communities and of all of 
their citizens. * 
Taking, therefore, the value of kerosene as proven, a 
word must be said as to the best grade of kerosene, and 
the best method of applying it. 
Ill choosing- the grade of the oil two factors are to be 
considered. First, it should spread rapidly. Second, it 
should not evaporate too rapidly. The heavier grades of 
oil will not spread readily over the surface of the water, 
but will cling together in spots, and the coating will be 
unnecessarily thick. Mr. W. C. Kerr, who conducted the 
extensive experiments on Staten Island, to which we have 
several times referred, tried several kinds of oil, and 
found to be best adapted a low grade of oil known as “ fuel 
oil,” supplied by the Standard Oil Company. Of the oils 
which he tried, some contained too much residuum of a 
thick nature which appeared as a precipitate, and could 184 
MOSQUITOES 
scarcely be pumped ; some were too thick in chilly weather 
and could not be pumped at all, while some were limp, 
easily handled, made a good uniform coating on the 
ponds, and were very effective. So long as the oil flows 
readily and is cheap enough, the end is gained, provided 
it is not too light and does not evaporate too rapidly. 
Mr. Matlieson, in his North Shore experiments, arrived at 
the same conclusion, and the petroleum which he found 
satisfactory for use on the mosquito-breeding ground was 
that known by the Standard Oil Company as “ light fuel 
oil.” 
In the accounts of the early experiments of the English 
observers in West Africa, it was found, according to their 
reports, that the petroleum which they placed upon runs 
was not persistent, and that it was necessary to renew the 
application at much more frequent intervals than has been 
found to be the case in this country. The explanation of 
this is undoubtedly that some light illuminating oil was 
used, which was more volatile than was at all necessary, 
and which at the same time was unnecessarily expensive. 
The army workers in Cuba have been advised by the 
writer to use this fuel oil of the Standard Oil Company. 
I am informed by the Standard Oil people that at the 
time Mr. Kerr’s work was being- carried on the price of this 
oil was $2.25 per barrel, but that in March, 1901, the price 
had advanced and was $3 per barrel, including the barrel, 
f. o. b. Point Breeze, Philadelphia, or Bayonne, N. J., an 
allowance for the barrel to be made upon its return, the 
allowance, however, depending entirely upon the condi- 
tion of the barrel when received by the Standard Oil ME ME DIES AGAINST MOSQUITOES 
185 
Company. It thus appears that this is not a high-priced 
oil, and very likely in case of large-scale community work 
it could be bought by the tank-car at a very reasonable 
rate. 
Kerosene may be applied simply by pouring' it upon 
the surface of the water, when it will spread of itself, or 
be spread rapidly by light winds, or it may be spread 
through a spraying nozzle. A spraying method was used 
successfully on Staten Island by Mr. Kerr and his asso- 
ciates. The laborers employed were furnished with 
bucket-pumps and were able to throw the spray into 
ponds for a considerable distance from the shore. The 
use of a spraying nozzle, however, does not seem to me 
to be desirable. I watched the oiling of ponds by this 
method at a New Jersey town, where the work was being 
carried on under the auspices of a ladies’ town-improve- 
ment association, in the early summer of 1900. The water 
treated was all in small woodland ponds and there was a 
great waste of kerosene. The spray was diffuse, and be- 
came scattered over the vegetation on the borders of the 
ponds, a large share of it being wasted in this way. On 
small ponds the oil can be sprinkled to advantage out of 
an ordinary watering-pot with a rose nozzle, or, for that 
matter, pouring it out of a dipper or a cup will satisfac- 
torily treat a small pond of, say a hundred square feet of 
water surface. With larger ponds, a pump with a straight 
discharge nozzle may be used. The straight stream will 
sink and then rise and spread, until the whole surface of 
the pond can be covered without waste. The English 
observers advise mopping the petroleum upon the surface 186 
MOSQUITOES 
of the water by means of cloths tied to the end of a long 
stick and saturated with kerosene. The use of such a 
mop may be desirable, even where a straight discharge 
pump has been used, in order to commingle two surface- 
sheets of oil. 
The question as to the frequency of application of 
kerosene is an important one. In my early experiments 
I found that the kerosene was effective for some days 
after the odor had disappeared and after the iridescent 
effect upon the surface of the water had ceased to be per- 
ceptible to the eye. A single application to a small pool 
was certainly effective from twelve to fifteen days. The 
persistence of the oil, however, will undoubtedly vary 
with the temperature and with the character of the pool 
—whether exposed to the direct rays of the sun or shaded 
by trees. It is, at all events, safe to say that it will be per- 
fectly effective under nearly all circumstances, for at least 
a week, and probably longer. That means that for a week 
no mosquito can alight upon the surface and succeed in 
depositing eggs, and that even if she could do so the 
larvae hatching from such eggs would be killed. There- 
fore we must calculate from the end of such an effective 
period to the end of the growth of larval and pupal life, 
and just before this second period is reached the applica- 
tion should be renewed. Under the most favorable cir- 
cumstances it will take from seven to ten days for a mos- 
quito larva to reach full growth, and the pupa to become 
ready to give out the adult. Therefore, to the kerosene 
week must be added at least a week of larval and pupal 
growth, which would require a second application of kero- REMEDIES AGAINST MOSQUITOES 
187 
sene after from fifteen to twenty days, in order to render 
it impossible that any adult mosquito can be developed. 
This period is too short, rather than too long, but it is ab- 
solutely safe, and in any given locality observations will 
indicate to -what extent it may safely be lengthened. I 
am quite inclined to believe that, even in tropical regions, 
seventeen-day intervals will be perfectly safe, if the fuel 
oil referred to above is used. My own experiments were 
carried on with illuminating oil, and the fuel oil is more 
persistent. 
The tirst army orders issued in Cuba (Circular No. 8, 
Headquarters Department of Western Cuba, October 15, 
1900) required the treatment of breeding-pools once a 
month. The second order (General Orders No. 6, Head- 
quarters Department of Cuba, December 21, 1900) re- 
quired the application of kerosene twice a month. The 
Winchester ordinance, it will be remembered, designates 
as the times of application once every three weeks, but 
the mayor suggests that the tirst and fifteenth days of 
each month be “ oil days.” 
As interesting records, tlie army circular and order are 
given .* 
{Circular No. 5.] 
Headquarters Department of Western Cuba, 
Quemados, October 15, 1900. 
The following communication from the Chief Surgeon is pub- 
lished for the information and guidance of commanding officers 
in this department. The necessary action will be taken as there- 
in recommended. 188 
MOSQUITOES 
Chief Surgeon’s Office, 
Headquarters Department of Western Cuba, 
Quemados, Cuba, October 13, 1900. 
To the Adjutant-General of the Department. 
Sir : 1 have the honor to invite your attention to the follow- 
ing facts and their bearing on the health of the command : 
The role of the mosquito in the transmission of certain diseases 
is now well established. The evidence is now perfect and con- 
clusive that malaria, as well as filarial infections, are carried by 
this insect, and there are reasons to suspect that it may be con- 
nected with the transmission of yellow fever, also. 
Every consideration of prudence, as well as comfort, demands, 
therefore, the protection from them of the commands at all posts. 
It is believed that this can be done with a very slight expendi- 
ture of time and trouble, by the enforcement by post commanders 
of two precautions, namely : 
1. The enforcement of the use of mosquito-bars in all barracks 
and especially in all hospitals. 
2. The destruction of the larvae of young mosquitoes, com- 
monly known as “ wiggletails ” or “ wigglers, ” by the use of 
petroleum on the water where they breed. 
The mosquito does not fly far, and seeks shelter when the wind 
blows ; so it is usually the case that every community breeds its 
own supply of mosquitoes, in water-barrels, fire-buckets, or un- 
drained puddles, post-holes, etc. An application of one ounce of 
kerosene to each fifteen square feet of water once a month will 
destroy not only all the young, but the adults who come to lay 
their eggs. The water in any cistern or tank is not affected in 
the least for drinking or washing purposes, if only it is drawn 
from below and not dipped out. For pools or puddles of a some- 
what permanent character, draining or filling-up is the best 
remedy. It is recommended that the medical officer who makes REMEDIES AGAINST MOSQUITOES 
189 
the sanitary inspections at each post be charged with the super- 
vision of the details of these precautions. 
Very respectfully, 
Your obedient servant, 
J. R. Kean, 
Major and Surgeon, U.S.Y., Chief Surgeon. 
By Command of Brigadier-General Lee : 
R. E. L. Michie, 
Assistant Adjutant- General. 
General Orders, No. G. 
Headquarters Department of Cuba, 
The Chief Surgeon of the Department having reported that it 
is now well established that malaria, yellow fever, and filarial 
infection are transmitted by the bites of mosquitoes, the follow- 
ing precautions will, upon his recommendation, be taken for the 
protection of the troops against the bites of these insects : 
Havana, December 21, 3900. 
1. The universal use of mosquito-bars in all barracks and espe- 
cially in all hospitals, and also in field service when practicable. 
2. The destruction of the larvae or young mosquitoes, com- 
monly known as “ wiggletails, ” or “wigglers,” by the use of 
petroleum on the water where they breed. 
The mosquito does not fly far and seeks shelter when the wind 
blows; so it is usually the case that each community breeds its 
own supply of mosquitoes in water-barrels, fire-buckets, post- 
holes, old cans, cesspools, or undrained puddles. 
An application of one ounce of kerosene to each fifteen square 
feet of water, twice a month, will destroy not only all the young, 
but the adult females who come to lay their eggs. The water in 
cisterns or tanks is not affected for drinking or washing purposes 190 
MOSQUITOES 
by this application, if only it is drawn from below and not 
dipped out. 
For pools or puddles of a somewhat permanent character, 
draining or filling-up is the best remedy. 
The medical department will furnish oil for the purpose above 
mentioned. 
Post commanders will carefully carry out these precautions. 
By command of Major-General Wood : 
H. L. Scott, 
Adjutant-General. 
Dr. Reed informs me that this order was drawn np by 
Colonel J. R. Kean, United States Army, Acting- Chief 
Surgeon of the Division of Cuba. Colonel Kean wrote, 
under date of January 12th, that he made the interval 
between the applications of kerosene twice a month in- 
stead of once a month, as he had been unable to find in 
Cuba an oil of sufficient diffusive quality over the surface 
of the water, which at the same time would be less vola- 
tile than the common illuminating kerosene. The lubri- 
cating oils experimented with did not spread readily. 
Mr. Kerr’s Staten Island experience was an extensive 
one and led to interesting results. He writes me : 
While I do not know liow long the protection was afforded 
by each treatment of the pond-surface, my judgment was that it 
covered a period of at least several weeks. I think much depends 
upon the surrounding natural conditions. An exposed pond 
reasonably clear of weeds and grass and with a fairly clean shore- 
line, liberally treated with a non-volatile fuel oil, is quickly 
covered with an oily scum, which the first wind blows over to one 
side. Then with a change of wind it is blown hither and thither, REMEDIES AGAINST MOSQUITOES 
191 
so that the pond is thus automatically treated over its whole sur- 
face by the shifting of the wind, so long as there is a surplus of 
oil present. If the pond is full of grass and weeds and the surface 
once becomes covered, there is, of course, much less shifting, but 
the accumulation of oil on the foliage keeps the surface well 
covered, and I assume that this is largely due to the oil working 
on and off the foliage more or less, due to the disturbance of the 
wind. In a perfectly sheltered pond ; for instance, in a deep 
hollow surrounded by large trees, quite protected from wind and 
containing more or less of weeds and grass, 1 think the oily scum 
stays fairly constant, and in thus referring to the surface-coating 
I mean that which is plainly visible, and it is possible, even prob- 
able, that there remains for much longer periods a minute film of 
oil over the whole surface, which is not observable through such 
means as I have used. 
The twenty-five or more ponds which were treated under my 
direction had the oil applied at somewhat irregular intervals, 
averaging perhaps once a month, and at no time did I find any 
mosquitoes during that whole summer in their vicinity. The 
mechanical difficulties of oil application, however, led to resort- 
ing to drainage, and therefore my experience with the oil meth- 
ods ceased. These were hill-top ponds, chiefly in the woods, 
while the large marsh areas were so meagrely treated on the 
edges with oil as scarcely to be considered as treated at all, and 
therefore with them no real experience was gained. 
I have thought—but had no opportunity to try the experi- 
ment—of anchoring one or more barrels filled with fuel oil in the 
pond ; for convenience perhaps placing them there in the winter 
when frozen over and boring small holes in the barrel while the 
oil is thick with the chill of cold weather. Then with the sum- 
mer’s heat this oil will ooze out and maintain the supply in 
places not accessible by other means. If on experiment the oil 
oozed out too freely, various expedients could be tried—such as 192 
MOSQUITOES 
making larger holes and filling them with wicking or oakum, 
through which the oil would filter slowly. Any such method, 
however, would probably meet some difficulties through the 
abundant dirty residue which such oil always contains, but I am 
very sure that such experiments would result in a method of 
automatic distribution of the oil from such anchored barrels. If 
the water is deep enough they could be sunk with stones, and 
with holes on the upper and lower sides, the oil would press up- 
ward by the difference in specific gravity and thus give a con- 
stant pressure on which to issue slowly. 
Mr. Matheson’s experience at Lloyd’s Neck did not 
fully coincide with that of Mr. Kerr in regard to the 
durability of the surface-film. He states that his experi- 
ments with oil upon a five-acre pond indicated that the 
fuel oil would maintain a film for about a week, -while the 
ordinary illuminating oil, with which he first experi- 
mented, would last only half that time, the light fuel oil 
being very much heavier in gravity than the illuminating 
oil. The periods for which the film persisted varied ac- 
cording to the weather. With a high northwesterly wind 
the film was broken and the oil driven on the lee shore. 
He believes that an application every twenty days would 
be perfectly effective, but the cost of a more frequent ap- 
plication was so slight that he did not care to take the 
chances and treated the pond mentioned about every two 
weeks. 
Persons who are reading up on tl mosquito question 
will naturally consult the works of the English and Ital- 
ian investigators, and it may be well to suggest that the 
word “ kerosene ” apparently does not occur in the Eng- 11EMEDLES AGAINST MOSQUITOES 
193 
lish language as spoken by Englishmen, who invariably 
term it paraffine or paraffine oil. To the Italians we are 
indebted for a useful expression, which we might just as 
well adopt, namely to “petrolize,” meaning to treat waters 
with kerosene. Example : The petrolization of mosquito- 
breeding pools is one of the most important measures to 
be undertaken in the warfare against mosquitoes. 
Many of the small-scale experiments which have been 
made, notably by the Italians, with a small number of 
mosquito larvae in small jars or puddles, are not so in- 
dicative of the results to be expected as are more natural 
and large-scale conditions. Mr. Matlieson tells me that 
he once took twenty-five larvae in a quart jar and cov- 
ered it with a thin film of common kerosene oil and no- 
ticed that in less than fifteen minutes all larvae were dead. 
At the same time he put a film of oil on the surface of a 
thirty-gallon tank, and at the end of an hour there were 
still some few larvae wriggling. He questions whether 
kerosene is as swift a larvicide if put on the surface of 
deep ponds, as it is on the surface of experimental jars. 
In my own work I discovered that where the oil was not 
distributed equally the larvae clustered in the free places 
and were able to support life for hours. 
Other Subdances Against the Early Stages of 
Mosquitoes. 
The last paragraph indicates plainly the fact that 
laboratory experiments with other substances must not 
be accepted as conclusive until the substances used are 194 
MOSQUITOES 
treated upon a large scale and out of doors, but if a labo- 
ratory experiment fails it may be taken for granted that 
the outdoor trial will fail even more disastrously. It is 
for the reason that the much-quoted experiments of Celli 
and Casagrandi were apparently small-scale experiments 
that we in the United States have been inclined to give 
little weight to them. They experimented with a great 
number of products and decided that petroleum, certain 
aniline dyes, and vegetable powders made from pyre- 
thrum or chrysanthemum plants (which form the so- 
called Dalmatian and Persian insect powders) are the 
only substances which are to be recommended. Of the 
aniline dyes they recommend especially a substance 
which they call in their published work “ Larycith 3,” 
and under this name the writer mentioned it in his Gov- 
ernment bulletin. Every effort was made to ascertain 
what this substance might be, and it eventually dawned 
upon me that it might be a misprint for “ Larvicide 3.” 
Under this apprehension, Mr. Matheson, who, by the 
way, is a manufacturing chemist, succeeded in obtaining 
samples of the substance and in analyzing it. He finds 
that it is nothing but dinitrocresol, which is an insecti- 
cide that was formerly highly recommended, but which 
is now scarcely used at all on account of its very poison- 
ous character. It was used, in a solution of one pound to 
fifteen gallons of water, against caterpillars in Bavarian 
forests, and has been used to some extent as a germi- 
cide in washing down the walls of sick-rooms and also 
in washing the outside of brewers’ casks to prevent 
mould and fungi. Its poisonous qualities would make REMEDIES AGAINST MOSQUITOES 
195 
it dangerous to use as an application to ponds. The 
pyrethrum powders are expensive and not thoroughly 
effective. 
The use of tar was suggested by Dr. Fielding-Ould, of 
the English West African Commission, and creosote oil 
has been suggested as a probable larvicide of value. Ex- 
periments made by the writer in the summer of 1900 with 
coal tar showed that this substance is slow in its action, 
not perfectly effective, and not at all persistent. Experi- 
ments with the two grades of creosote oils (by-products 
in the manufacture of illuminating gas) indicated that 
they destroy the larvae, but not nearly so rapidly as the 
various grades of kerosene. It is possible that the creo- 
sote oils may prove to be more permanent than the 
lighter illuminating oils, though they are not as rapid in 
their effect and not as satisfactory, on the whole, as the 
grade known as fuel oil. 
A great deal lias been said about tlie value of perman- 
ganate of potash as a larvicide for mosquitoes. In the 
summer of 1898 a paragraph was copied in nearly all of 
the newspapers of the country, which was attributed to 
the Public Health Journal, and which read as follows: 
Two and one-half hours are required for a mosquito to develop 
from its first stage, a speck resembling cholera bacteria, to its 
active and venomous maturity. The insect in all its phases may 
be instantly killed by contact with minute quantities of perman- 
ganate of potash. It is claimed that one part of this substance in 
1,500 of solution distributed in mosquito marshes will render the 
development of larvae impossible ; that a handful of permangan- 
ate will oxidize a ten-acre swamp, kill its embryo insects, and keep MOSQUITOES 
19G 
it free from organic matter for thirty days, at a cost of 25 cents ; 
that with care a whole state may be kept free of insect pests at a 
small cost. An efficacious method is to scatter a few crystals 
widely apart. A single pinch of permanganate has killed all the 
germs in a 1,000-gallon tank. 
The item is so obviously ridiculous upon its face that 
it would hardly seem worth while to make any attempt to 
refute its statements. Nevertheless, it has been so widely 
read that definite experimentation seems necessary to set 
the matter at rest. The unknown author’s ignorance of 
the life history of mosquitoes in the opening sentence 
need not necessarily imply that he would not know a good 
remedy if he found one. Careful experiments were under- 
taken by the writer in July, 1898, with various strengths 
of permanganate of potash, in water containing mosquito 
larvae from one to six days old. It was found that small 
amounts of the chemical had no effect whatever upon the 
larvae, which were, however, killed by using amounts 
so large that, instead of using a “ handful to a ten-acre 
swamp,” at least a wagon-load would have to be used 
to accomplish any result. Moreover, after the use of 
this large amount and after the larvae were killed, the 
same water, twenty-four hours later, sustained freshly 
hatched mosquito larvae perfectly, so that even were a 
person to go to the prohibitive expense of killing mos- 
quito larvae in the swamp with permanganate of potash, 
the same task would have to be done over again two days 
later. 
The same conclusion was subsequently reached, after 
careful experiment, by Dr. Lederle, of the New York REMEDIES AGAINST MOSQUITOES 
197 
Health Department, and by the Italians Celli and Casa- 
grandi. 
After all, we are practically reduced to the use of oils 
in this larvicidal work. The question will naturally arise, 
“ Are there any other oils which can be used to better 
advantage than the best petroleum oils ? ” Mr. Matheson 
suggested to me the use of corn-oil, a substance which is 
rather extensively made in certain parts of the country and 
which, considering the enormous crops of corn grown in 
our Western States, which, in fact, are so great that some- 
times in years of over-production the grain is burned as 
fuel, might reasonably be supposed to be a cheap oil. At 
present, however, that does not seem to be the case, and 
its price in the ordinary market is prohibitive, as com- 
pared with ordinary kerosene. Nevertheless, experiments 
were undertaken with samples received from Mr. Mathe- 
son. It was found that the corn-oil did not spread readily 
and that it gathered together in large patches. Mosquito 
larv?e rising to the surface of the water, and finding them- 
selves under a patch of oil, simply wriggled violently 
until they found the spaces between the patches, where 
they breathed comfortably and lived for several days. In 
this experiment the main object was to secure a persist- 
ent oil which would not evaporate, but would remain for 
at least several weeks over the surface of the water. The 
non-spreading qualities of corn-oil, however, as well as its 
price, remove it from the list of good culicides. 
Although a number of proprietary and secret mixtures 
for mosquito-breeding pools have been sent to the writer 
for experiment, none of them have been found more satis- 198 
MOSQUITOES 
factory than the cheapest petroleum, and none of them 
are recommended. In a work of this kind we need not 
only the best but also the cheapest substances. The large 
scale on which this work is undertaken, and will be under- 
taken in the future, demands a cheap substance, and on 
the whole there can be no doubt that the kerosene known 
as fuel oil will be found to be the most satisfactory. Of 
course, the general interest in the subject will induce 
future additional experimentation, and it is quite within 
the possibilities that something better will be discov- 
ered. Up to the present time, however, nothing definite 
is known. 
The Abolition of Breeding-Places by Drainage or by 
Filling. 
Iii the chapter on mosquitoes and malaria is given an 
account of how, by an expenditure of forty dollars for 
drainage in the summer of 1900 in a Maryland village, 
malaria practically ceased to exist, although the previous 
summer there had been one or more cases in every family 
in the village. That meant that the breeding-places of 
Anopheles were abolished. And it should be added that 
the numbers of mosquitoes of the genus Culex were vastly 
reduced by this operation. Those which remained prob- 
ably bred in artificial water-receptacles, such as tanks, 
tubs, or barrels, not a part of the former permanent supply 
of the place. This is probably one of the most striking 
instances of the value of drainage with which this section 
could appropriately be introduced. REMEDIES AGAINST MOSQUITOES 
199 
In the summer of 1900, at a certain army post, about 
one-half of the soldiers were ill with malaria. The hospital 
was not screened, Anopheles were found upon the walls of 
the malarial ward, bit the malarial patients in their beds, 
flew out and bit the sentry on guard, and generally be- 
haved themselves in a highly indecorous manner. The 
early part of the summer was wet, then came a long dry 
spell. After the drought had continued for some weeks I 
visited the post, and within a few hundred feet of the 
door of the hospital found a slight depression in the 
ground which had contained a surface-pool of water. The 
water had entirely evaporated during the dry spell, but 
the drying mud at the bottom was fairly carpeted with 
the empty pupa skins of Anopheles. This was the only 
trace of the early stages of Anopheles found in the 
vicinity. This small depression could have been filled up 
with two cart-loads of earth, and had this been done at 
the proper time it would not have been responsible for the 
birth of a single Anopheles, whereas it had been respon- 
sible certainly for several thousands. This is as good an 
example as could be desired of the desirability and feasi- 
bility, as well as economy, in many cases, of filling up 
breeding-places with earth. 
There can be no doubt that there are many cases where 
a little drainage-work such as was done in the Maryland 
town, or a little filling-in such as was needed at the army 
post, will accomplish striking results in the way of reduc- 
ing the numbers of mosquitoes. There are also many 
other places where drainage or filling-in upon a large 
scale would be desirable and necessary. It is difficult in 200 
MOSQUITOES 
any case, and entirely without reference to the question 
of mosquito-supply, to see why swamp-land should be 
allowed to exist. There are many large tracts of swamp- 
land which could be drained with a comparatively slight 
expenditure of money, and which, when once reclaimed, 
would be of very great value for agricultural purposes. 
There is a great deal of this land in the immediate vicin- 
ity of many large communities which suffer from the at- 
tacks of mosquitoes and which are more or less malarious. 
In such instances, community drainage-work should be 
undertaken for the health and comfort of the community. 
Misguided owners of swamp-land, if they cannot be made 
to see that such measures would bring dollars and cents 
into their pockets, should be coerced. 
Iii many cases such drainage or swamp-reclamation is 
an expensive and a more or less complicated matter. The 
swamps, for example, on the borders of the Great Lakes, 
and of the smaller lakes which abound in central New 
York, in Wisconsin, and at other points, cannot be thor- 
oughly reclaimed without the expenditure of large 
amounts of money. The same maybe said for such great 
brackish marshes as the Hackensack meadows in the 
vicinity of New York City and the great stretches of 
high marsh-land, occasionally overflowed only by the 
highest tides, which exist at many points along the At- 
lantic coast. In such cases even large communities will 
not be apt to undertake the responsibility of drainage 
and diking measures on account of the expense. This 
means that such measures should be adopted by States. 
A good practical state drainage law is in these dajrs a REMEDIES AGAINST MOSQUITOES 
201 
practical necessity, and the adoption of such laws by many 
States should be actively urged and will be furthered in 
the immediate future. 
In the annual report of the State Geologist of New 
Jersey for the year 1899 (Trenton, N. J., 1900), it is shown 
that the general drainage laws of the State provide for 
the improvement and reclamation of the wet lands of the 
State, both tidal or salt meadows and wet fresh-water 
lands. “ On the application of at least five owners of 
separate lots of land, included in any tract of land in the 
State which is subject to overflow from freshets, or which 
is usually in a low, marshy, boggy, or wet condition, 
the Board of Managers of the Geological Survey is au- 
thorized to make surveys of such tract or tracts and to 
adopt a system of drainage for the same.” The plans and 
surveys are submitted to the Supreme Court, and com- 
missioners to do the work are appointed by the court. 
Under the head of “ The Reclamation of the Hackensack 
and Newark Meadows,” in the same report, the improve- 
ment of four thousand acres within the corporate limits 
of Newark is proposed, that within the corporate limits of 
Jersey City and Elizabeth having been handled by those 
cities. The extension of the city of Newark over the 
marshy tract to the deep water of Staten Island Sound 
would be made possible by reclamation-work. The de- 
preciation of value and real estate near the meadows, and 
the increase which would follow the reclamation, are 
strong arguments, aside from the sanitary benefits to be 
gained. In the case of the Newark meadows, a report by 
C. C. Vcrmeule showed that the city, on advertising for 202 
MOSQUITOES 
plans and proposals, found that the marsh could be ren- 
dered suitable for occupation at a contract cost not ex- 
ceeding $300 per acre, an amount which, when compared 
with the selling price of city lots in Newark, is very small. 
Drainage not for city purposes, however, Mr. Vermeule 
shows, can be done for about $93 per acre. This would 
put the land in condition for agriculture or grazing. He 
shows that in Nova Scotia, drained marsh-lands sell for 
$150 to $200 an acre for agricultural purposes only, and 
that the diked meadows in Salem and Cumberland Coun- 
ties in New Jersey have always been worth several tunes 
as much as improved upland. “As much as fifty-five 
bushels of wheat per acre, and heavy crops of hay are 
raised on them. A moderate amount of drained tide- 
marsh attached to a farm in that vicinity enhances the 
value of the farm.” He urges that a private corporation, 
if it can secure a sufficiently large area to begin opera- 
tions, and can drain it and put a small portion under cul- 
tivation as a demonstration, could promptly lease the 
rest for enough money to give a fair return on the invest- 
ment, and the appreciation in the value of the land in 
the course of a few years, since it is so near New York, 
would undoubtedly make the venture profitable. 
An editorial in the New Jersey Advertiser of February 
9, 1901, advocates work under the Board of Trade against 
mosquito-breeding places. The reasons are summed up 
well in the following words : 
“ There is a sanitary reason for their extirpation. They 
injure property for sale, so there is a good economic rea- 
son. They afflict the healthy, and torment the sick, and REMEDIES AGAINST MOSQUITOES 
203 
the bad name they give a locality keeps population away. 
A crusade against the mosquito plague should go hand in 
hand with local enterprise. The abolition of the pest 
would be the greatest victory achieved in the whole 
career of the Newark community.” 
They show that Newark has a magnificent water-sup- 
ply ; possesses a large park area; is about to build a 
city-liall, is to cleanse the Passaic River of its filth, and 
dredge it to make a larger channel. Finally it is urged 
that the meadows be reclaimed, and that the marshes 
along the bay be diked. 
The Hoboken (N. J.) Observer, under date of October 8, 
1900, says that the draining of the meadows and other 
low lands lying between Hoboken and Jersey City, and 
between Jersey City and the Passaic River, has become 
an urgent matter and has long been agitated from a com- 
mercial standpoint, but these fens and meadows are 
breeding-places for mosquitoes. Reports of the bureaus 
of vital statistics show that the majority of deaths are 
caused by zymotic diseases. 
Tlie Roman correspondent of the London Standard of 
January 14, 1901, states that the annual parliamentary 
report on the measures for improving the sanitary con- 
ditions and promoting the agricultural prospect of the 
Roman Campagna shows that, while the rural popular 
district is constantly increasing, fever becomes more and 
more rare. The proportion of fever-stricken land has 
been reduced fifty per cent, by these measures. The cul- 
tivation of the region under the new conditions has in 
many instances yielded splendid results, and a number 204 
MOSQUITOES 
of private individuals are investing considerable capital 
in carrying out further improvements. 
The question of drainage-work was treated very inter- 
estingly and convincingly by Mr. H. C. Weeks, of Bay- 
side, Long Island, in the Scientific American Supplement, 
January 5, 1901. The following paragraphs are taken 
from this important article. 
There are many causes which militate against reclaiming 
marshes, which must be done before the largest factor in the 
spread of mosquitoes is eliminated. Generally they are held in 
small tracts by a number of owners, and the more the owners, 
the greater the difficulty of action. This fact suggests the neces- 
sity of every state having, as some places have, drainage laws 
that would relieve such a situation. And that leads to the 
statement of the necessity of some legislation preventing a small 
interest in a tide-stream, owned by a few, and used but little, 
overriding the general interest and preventing a drainage scheme 
that would improve the health and material interests of a large 
territory, as well as relieve it of mosquitoes. In passing—how 
often does it occur that a train-load of passengers is held up by 
an open bridge over a little stream, and the cause of it all, a 
sailor standing on his rights and unconcernedly waiting for the 
tide or wind to bear his little craft through the draw. Such 
things are contrary to the spirit of the age, and should be rem- 
edied. 
Another difficulty is found in the fact that owners, as a rule, 
are not informed of the financial side of the case, and they are 
unwilling, sometimes unable, to invest in a plan for reclamation 
that will mean an outlay to them, when there is already an in- 
come in the salt hay produced, though generally this is of no 
net profit. 
There is, too, a great lack of information on the general sub- REMEDIES AGAINST MOSQUITOES 
205 
ject of the reclamation of marshes, and their producing-value is 
little understood. All know, of course, in a general way, of the 
notable instance in the case of Holland ; but that nearly a mill- 
ion acres have been rescued from the sea under the greatest dif- 
ficulties and expense in that land, and have been made to pay 
on the investment, is not fully realized. And the same may be 
said on this continent in the upper and middle Atlantic sea- 
board, as well as on the Pacific side. Many marshes are of allu- 
vial formation, and there are numerous instances of the contin- 
uous production of enormous crops of almost every kind for 
scores of years without the use of any fertilizers. Cases exist, 
however, of persons being unwilling to be convinced, and contin- 
uing their opposition even after a successful reclamation, as are 
seen in the official records of Massachusetts, where examinations 
by the state have shown a great improvement in the sanitary 
and agricultural conditions. In the instance of Green Harbor, 
in that state, it is shown that the death-rate of the reclaimed 
district averages lower than the general death-rate of the 
state, that there is a steady increase in summer visitors, and 
that many houses are being built. The testimony of persons 
of wide knowledge and ample experience in the science and art 
of agriculture is adduced, showing the good results in that field, 
and yet it fails to silence opposers. Besides mentioning the re- 
markably heavy crops of hay, much preferred by his horses to 
the best from the uplands, also the excellent crops of strawber- 
ries and vegetables raised in these lands, one such qualified ob- 
server gives his experience as to asparagus in such convincing 
words that they are quoted in full : “ While visiting the Marsh- 
field Meadows on April 19, 1897, I found asparagus already up, 
very nearly high enough to cut. I was surprised at this, for my 
own asparagus had but just appeared above the surface of the 
ground, although growing on land so warm that I am usually 
first to ship native asparagus to Boston market. I was also sur- 206 
MOSQUITOES 
prised at the size of the stalks, they being much larger than the 
first set of stalks that appear on my land. When I consider the 
fact that the land on which this asparagus was growing has pro- 
duced large crops every year for twenty years, without fertilizers 
of any kind, and still produces better crops than my land, which 
has had $600 worth of fertilizers to the acre applied to it during 
the last twenty years, it convinces me that this land, for garden 
purposes, surpasses any which I have ever examined. . . . 
We realize, in a measure, the great value of the material which 
nature has for ages been storing up for man’s future use, if he 
be wise enough to avail himself of it.” 
It has been too frequently thought that to throw up an em- 
bankment to keep out the waters, and to build sluices and gates 
to let the interior water out, were all that was requisite; and, 
under this mistaken view, many instances have occurred greatly 
to the loss of the persons interested, and to the prejudice of the 
whole subject. An eminent engineer has said of reclamation : 
“ What at first sight seems a mere mud and water proposition 
really requires,for its proper economic development, the best prod- 
uct of the latest practice in several fields of engineering and other 
sciences. Although the method of reclamation is centuries old, 
it may now be worked out by the aid of much that is novel in 
methods of construction and operation. ’ ’ 
Successful reclamation requires a most careful consideration of 
all the conditions existing, which generally vary in some feat- 
ures at every point, and not the least of the difficulties to be met, 
and one which to-day accounts for many expensive failures, is 
the ravages of the musk-rat, and yet even he can be circumvented 
with proper care. Unsuccessful reclamations can all be accounted 
for by the neglect of some important point. A partially drained 
marsh is, no doubt, in a worse sanitary condition—more pesti- 
ferous and pestilential—than if not drained at all, and for most 
crops it is likewise a failure. Besides, the soils in all marshes are REMEDIES AGAINST MOSQUITOES 
207 
not suited to the raising of crops, and one reclaiming-failure, 
even on that account, seems to offset many successful ones. Care 
must be had in allowing for the subsidence of the marsh, which 
occurs in more or less degree, depending upon the character of 
the soil. Usually, where the marsh-level is sufficiently above 
mean low tide, reclamation can be effected without the use of ar- 
tificial means to care for the inner water. 
The cost of maintaining effective reclamation is slight if thor- 
oughly done in the first instance, but otherwise, becomes expen- 
sive and discouraging, and there are many fields once successfully 
reclaimed but now overflowed, resulting from the attempt at sav- 
ing a few dollars per acre in the original work. 
While it may be argued as against reclamation that there is 
plenty of cheap land without spending good money to obtain 
more acreage, yet this is not the way to dispose of the fact that 
these marshes are the prolific breeding-ground of mosquitoes, 
and that mosquitoes—how many kinds is not ascertained—bear 
the germs of a disease that, in its great prevalency, does more to 
reduce the vigor, which is largely the capital, of a nation, than 
any other disease. 
Mr. Weeks’s mention in this article of the crops that 
can be grown upon reclaimed swamp-lands reminds me 
that Professor Milton Whitney, Chief of the Division of 
Soils of the United States Department of Agriculture, has 
told me that the value of drained salt marsh lands is very 
great for meadow purposes, and that when well drained, 
so as to prevent any danger of seepage waters coming 
near the surface, they are valuable for truck crops, if 
situated within easy reach of markets. 
In the work which was done by the Richmond County 
Chib of Dongan Hills, Staten Island, under the leader- 208 
MOSQUITOES 
ship of Mr. W. C. Kerr, of the firm of We still "house, 
Church, Kerr & Co., New York, to which we have several 
times referred, considerable drainage of fresli-water 
swamps above the seacoast bluffs was carried on with 
great success and at a minimum of expense. This work, 
together with the use of kerosene upon larger pools, re- 
sulted in complete relief from the attacks of the fresh- 
water mosquitoes, which during the early summer had 
always been numerous and ferocious, but down the bluffs 
below the Club there was a large area of salt-marsh, and 
in the higher portions of this marsh-land the brackish 
water-mosquito of the Atlantic coast (Culex sollicitans) 
breeds abundantly and puts in its appearance up to the 
end of July in numbers. An attempt by members of the 
club was made to buy this land in order to dike and drain 
it, with the idea that it could subsequently be let to truck 
growers, access to New York markets being easy and 
profits for truck farming in that vicinity being great. In 
the attempt, however, they found a singular obstinacy on 
the part of the owners of this worthless land, and the 
attempt was, at least temporarily, abandoned. 
A successful effort of this kind, however, has been re- 
corded by the writer in a previous publication. It conies 
from one of the editors of the Scientific American, who 
writes as follows: 
In the town of Stratford, Conn., where I have resided for the 
past forty-five years, we have been greatly plagued by swarms of 
mosquitoes, so great, in fact, that the “ Stratford mosquito” be- 
came a well-known characteristic of Stratford. We have in the 
southern part of our town, bordering on the sound, several acres REMEDIES AGAINST MOSQUITOES 
209 
of marsh-land or meadow, which would become periodically 
overflowed with water in the summer and a tremendous breeding- 
ground for mosquitoes, and this plague to the town continued 
until about 1890-91, when a party from Bridgeport, Conn., pur- 
chased a large section of the meadows and began to protect them 
by a dike, both on the north and south ends, which shut out the 
water. In addition to this, numerous drain ditches were made 
which helped to carry the water away. The result of this work 
made the land perfectly dry and spongy, so that after a rain no 
pools collected on the surface of the meadow and the creation of 
the mosquitoes was prevented. The transformation was so re- 
markable that people outside the town would hardly believe that 
it had been effected, and a year or two later the town voted a 
special appropriation of $2,000 to the party who undertook to 
build the dike and render the meadows mosquito-proof. It had 
also the effect of placing on the market a large tract of land ele- 
vated from the sound, for residences, and as many as twenty-five 
summer residences have been built upon this land bordering on 
the sound, and the number is increasing each year. They are free 
from mosquitoes, so that the operation shows the economy and 
the benefit that will result by using some means for eliminating 
the mosquito-breeding pools. 
As lias been pointed out on earlier pages, nearly all of 
our mosquitoes breed exclusively in fresli water, and none 
of the forms which inhabit the United States, so far as 
ascertained, will breed in sea-water. Therefore, under 
certain peculiar conditions, another remedy is indicated 
by this fact, namely, that near the seashore, by a certain 
amount of ditching, the water of ponds may be converted 
from fresh to salt. A rather large-scale operation of this 
kind was conducted a few years ago at Virginia Beach, 210 
MOSQUITOES 
the well known seacoast resort directly east of Norfolk, 
Ya. Behind the hotels at this place, in former days—the 
hotels themselves fronted upon the beach—was a large 
fresh water lake, which, with its adjoining swamp, was a 
source of mosquito-supply, and it was further feared 
(although this was before the mosquito-dissemination of 
malaria was proven) that it made the neighborhood mal- 
arious. Canals were cut, and the water of the lake was 
changed from a body of fresh to a body of salt water. 
The lake is now supplied with salt water at daily high 
tides by an underground feeder. Crabs and small fish 
occur in the lake in numbers, and no mosquito larvae 
are to be found even in August, even in the swampy 
places at the lake border. The water itself is very salt to 
the taste, and samples which have been tested at my re- 
quest by Mr. E. E. Ewell, a chemist, showed that the 
total chlorine contained in the samples, calculated as so- 
dium chloride, is equivalent to 22.88 grams of that salt per 
liter, or 1,330 grains per United States gallon, or 3.05 
ounces (avoirdupois) per United States gallon. The chlor- 
ine contained in sea-water is equivalent to 31.15 grams of 
sodium chloride per liter. The samples from Virginia 
Beach, therefore, contained approximately two-tliirds of 
the quantity of salt usually present in the sea-water. 
Even where states or communities cannot be induced to 
take up the question of marsh drainage and diking, it is 
possible for public-spirited individuals of means to do 
work in this direction which will count. For example, it 
is planned by a company of wealthy men who have sum- 
mer homes on the north shore of Long Island, in the REMEDIES AGAINST MOSQUITOES 
211 
vicinity of Oyster Bay, Cold Spring Harbor, Lloyd’s Neck, 
and Center Island, to spend several thousand dollars in 
this kind of work during the summer of 1901, with the 
sole view of reducing the summer mosquitoes of that 
region. This is mentioned as an indication of what might 
be done at other points. 
Introduction of Fish into Fishing Ponds. 
It happens quite often that larger or smaller ponds will 
be found which for some reason or other are considered 
too valuable to drain, and which the owners will not per- 
mit to be treated with kerosene, and yet in which mos- 
quitoes breed abundantly. Such ponds will, as a rule, be 
found to be milldams, ice-ponds, or pools artificially con- 
structed with rock and cement bottoms for the purpose 
of watering stock. Into such ponds it becomes absolutely 
necessary to introduce fish that will destroy mosquito 
larvae, which will otherwise invariably be found to exist in 
them in great numbers. 
The subject of the appropriate tisli to use for this pur- 
pose has been considered in Chapter VII., and to that 
chapter the reader is referred. 
Remedies Against Adult Mosquitoes. 
In regions where mosquitoes abound, all houses must, 
as a matter of course, be thoroughly screened, if a meas- 
urable degree of comfort is to be gained. The extreme 
importance of the careful screening of windows and doors 212 
MOSQUITOES 
in malarious neighborhoods cannot be too strongly in- 
sisted upon, wherever there is any reason to suppose that 
any work which may have been carried on against breed- 
ing-places may not have been so thorough as to be effect- 
ive. If mosquitoes of the malarial genus Anopheles 
once gain access to a house they will remain hidden 
behind curtains or somewhere upon the walls during 
the day and at night fly out about the rooms in their 
search for persons to bite. Some observers of tropical 
countries say that in unprotected houses, Anopheles 
will frequently fly out and hide outside during the day, 
returning to the houses at night, but by far the more 
usual method seems to be to stay indoors. In addition 
to this screening, it is recommended that in tropical 
countries all the indoor walls of houses should be 
painted white or whitewashed, in order that the dark 
bodies of the mosquitoes may plainly be seen and that 
they may easily be caught. However, when the walls are 
not white and when the insects are hidden behind hang- 
ings or behind old-fashioned beds or elsewhere, they 
may be driven out of their hiding-places with smoke and 
will then settle on the window-panes in the hope of es- 
caping. 
To kill living- mosquitoes in Louses, Fermi and Lum- 
bao recommend clilorine g-as. Pour into a dinner plate 
containing four or five spoonfuls of chloride of lime five 
to ten cubic centimetres of crude sulphuric acid. This 
liberates the chlorine gas, which kills the mosquitoes. 
The same writers state that the vapors of chloral act rap- 
idly, killing them in a few seconds, though these vapors REMEDIES AGAINST MOSQUITOES 
213 
can be used only in rooms which are not inhabited, or in 
which the vapors can be permitted to remain for several 
hours. 
The burning of pyrethrum powder in such a room, 
when done in a proper way, will also kill the mosqui- 
toes or, at least, stupefy them. The pyrethrum powder 
should be moistened somewhat and moulded into little 
cones, which are then dried in the oven. When one of 
these cones is ignited at its summit by a match it will 
smoulder slowly, filling the room with smoke, which to 
most people is not unpleasant, and which smells much 
like the sticks of punk which boys use to light fire- 
crackers. This smoke seems to stifle the mosquitoes, 
which fall to the floor. Two or three of these cones 
burned in a room in an evening will give relief by stupe- 
fying the insects, but on a warm summer night they will 
not take the place of screens, since the windows must be 
closed in case of any movement of the air, otherwise the 
smoke is not effective. 
The use of tin cups or inverted can-covers, the shal- 
lower the better, nailed to the end of a stick and contain- 
ing- a very small quantity of kerosene, is very prevalent in 
some parts of the country for catching mosquitoes resting 
on the ceiling. Where the ceiling is white, the mosqui- 
toes can readily be observed and the tin cup is pushed up 
under them. When they attempt to fly they are caught 
by the kerosene and killed. I have seen dozens of them 
caught in this way of an evening in a mosquito-infested 
house. The first time I ever saw the apparatus was about 
1890, in a New Jersey town. When about to retire to my 214 
MOSQUITOES 
bedroom at night one of these stick-cups was given to me 
with a description of how it was to be used. I was too 
sleepy to experiment, however, and went to bed. On 
wakening the next morning I thought of the experiment 
and tested it with great success. Eighteen mosquitoes 
were caught on the ceiling of the bedroom, but as every 
one of them was full of blood, I regretted that the use of 
the instrument had come as an after-thought. 
Celli and Casagrandi state that the substance which 
they call Larycith III, which (if I am correct in suppos- 
ing it to be a misprint for “ larvicide ”) is dinitrocresol 
—a yellow aniline color—will when burned in small quan- 
tities, kill the adult mosquitoes, and that this method con- 
stitutes the most efficacious method of destroying them. 
The Chinese use pine or juniper sawdust, mixed with a 
small quantity of brimstone and an ounce of arsenic, run 
into slender bags in a dry state. Each bag is coiled like 
a snake and tied with thread. The outer end is lighted. 
Two coils are said to be sufficient for an ordinary room, 
and 100 coils sell for six cents. 
There have been many substances recommended for 
use upon the skin in order to discourage mosquitoes. 
Camphor, rubbed upon the face and hands, or a few drops 
upon the pillow at night, will keep away mosquitoes for 
a time, and this is also a well-known property of oil of 
pennyroyal. The use of oil of peppermint, lemon juice, 
and vinegar have all been recommended for use as pro- 
tectors against mosquitoes, while oil of tar is also used 
in bad mosquito localities. Dr. John B. Smith writes 
that in the matter of preventives, in his experience notli- REMEDIES AGAINST MOSQUITOES 
215 
ing is equal to oil of citronella. He has used this on the 
seashore with great success for three summers, and has 
recommended it to gunners and others, who have re- 
ported good results. Mr. E. H. Gane, of the firm of Mc- 
Kesson & Robbins, of New York, informs me that the 
essential oils which he has found most effective in keep- 
ing away mosquitoes have been the oils of lavender, cit- 
ronella, and eucalyptus, in the order named. The sub- 
stance, however, which he has found to work with most 
perfect success is castor oil. He wrote under date of Oc- 
tober 3, 1900, “ Of course the application of this oil in its 
natural state is almost as objectionable as the bite of the 
insect, but by dissolving it in alcohol and adding some 
kind of essential oil or perfume, a preparation can be 
made which is not objectionable to most people and is 
very effective as a preventive of mosquito bites. The 
formula which I have been using with great satisfaction 
is: Castor oil, 1 ounce; alcohol, 1 ounce; oil of lavender, 
1 drachm. The solution should not contain less than fifty 
per cent, of the oil, to be satisfactory in all cases. 
Eucalyptus. 
In addition to tlie use of eucalyptus oil to keep mos- 
quitoes from luting1, as mentioned in the previous para- 
graphs, the growth of eucalyptus trees is said by certain 
persons to drive mosquitoes away, and trees of the genus 
Eucalyptus have been especially recommended for plant- 
ing in malarial regions. In 1893, Mr. Alvali A. Eaton, of 
California, wrote that in portions of California where the 21G 
MOSQUITOES 
blue gum occurs no other remedy need be sought for. 
Further than that, he stated that no matter how plentiful 
the mosquitoes are, a few twigs or leaves laid on the pil- 
low at night will secure perfect immunity. The same year, 
Mr. W. A. Sanders, of California, wrote that he had planted 
eucalyptus trees nineteen years previously about his 
house and that they had reached, some of them, a height 
of 140 feet. An irrigating ditch ran through the grove, 
but there was never a single mosquito larva in the ditch 
in the grove, although on both sides of the grove larvae 
were plentiful. In the grove, mosquitoes Avere never 
found, though outside they Avere plentiful. This seems 
very strong evidence, but there is also eATidence to show 
that eucalyptus trees are not at all effective. Dr. Alfredo 
Duges, the Avell known naturalist of Guanajuato, Mexico, 
wrote me on September 8, 1900 : “ I have received your 
very interesting study of the mosquitoes of the United 
States, and thank you greatly for it. At the end of the 
book you speak of the utility of eucalyptus for driving 
aAvay insects. I have had some experience with these 
trees. The fresh leaves placed upon the pilloAV will 
attract mosquitoes. Thinking that the mosquitoes loA7ed 
this plant, I have placed the branches farther aAvay, but 
without result. I have burned the leaves in my chamber, 
and the cursed beasts have resisted the smoke.” Dr. 
Nuttall states that malaria still prevails in certain local- 
ities outside of Rome, in spite of eucalyptus plantings. REMEDIES AGAINST MOSQUITOES 
217 
The Castor-oil Plant. 
A great deal was said in the newspapers during the 
winter of 1900-01 about the planting of the castor-oil 
plant to prevent mosquitoes. These notes were all based 
upon a consular report from Captain E. H. Plumacher, 
United States Consul at Maracaibo, Venezuela. The dis- 
patch, which was taken from Consular Report No. 216, 
March, 1901, reads as follows : 
A simple remedy against mosquitoes has been employed in sev- 
eral places in South Africa, and is equally well-adapted to the 
temperate zone. It consists in planting the castor-oil plant (Kici- 
nus communis), or “Palma Cliristi,” around the house and 
premises. 
In cold and temperate climates the castor-oil plant grows to a 
height of four or five feet; in these countries, it becomes a tall 
tree and is perennial. It seems that the smell of the plant is dis- 
agreeable to mosquitoes and other insects, and it is an acknowl-. 
edged fact that where these plants grow, few mosquitoes will be 
found. 
My personal experience bears this out. My residence is sur- 
rounded by plantain and banana trees, and I have been much 
troubled in the past by the great number of mosquitoes which 
gathered between the leaves. Following the example of old 
settlers in the country, I planted the castor-seeds, which grew 
up in profusion, and there are now no mosquitoes to be 
found among the plaintain and banana trees, although I keep 
the ground well irrigated- By keeping the branches and the 
seeds of the plant in rooms, the mosquitoes are driven away from 
the latter. 
There are several varieties of the castor-oil plant. In this coun- 218 
MOSQUITOES 
try there are two—one with brown nuts, and the other white in 
color, with a kernel tasting like the fresh almond. 
Maracaibo, November 30, 1900. 
(Copied from Consular Reports, No. 240, March, 1901.) 
E. H. Plumacher, Consul. 
Persons familiar with this plant, and who have had it 
growing in their gardens, tell me that although they have 
heard the idea advanced before, they are convinced that 
there is nothing in it, and that the growth of this plant 
does not drive away mosquitoes. 
Remedies for the Bites. 
As elsewhere pointed out, different persons differ 
greatly in the effects which the mosquito-poison produces. 
Some persons are scarcely troubled by the puncture, 
while others are quite severely poisoned. It has been my 
own experience that if I can only refrain from scratching 
after having- been bitten, no swelling results, and the irri- 
tation soon disappears. Even a small degree of scratch- 
ing, however, such as the rubbing of one’s cuff, or coat- 
sleeve, or collar, increases the irritation and produces 
a swelling, and sometimes white spots. Household am- 
monia has been found by many persons to give relief, and 
others say that a single touch of alcohol stops the irrita- 
tion. Dr. E. O. Peck, of Morristown, N. J., has written 
me that he has found glycerine a sovereign cure for the 
bites. Touch the bite with glycerine and in a few minutes 
the pain is gone. He says also that glycerine takes the 
pain from bee stings. Dr. Charles A. Nash, of New York REMEDIES AGAINST MOSQUITOES 
219 
City, lias written me that whenever a mosquito bites him 
he rubs the spot and marks it with a lump of indigo. 
This, he says, instantly stops the irritation, no matter 
whether the application is made instantly, or after the 
lapse of a day or so. He stated that he has used it since 
1878, and has a good opportunity to test it, for lie lives in 
a locality where mosquitoes are abundant. IX 
How to Collect and Preserve Mosquitoes 
Including1 an Account of How to Raise Mosquitoes and 
Study the Early Stages. 
ADULT mosquitoes are very fragile creatures. The 
scales upon tlieir bodies and legs are easily rubbed 
off, and the antennae, and especially the legs, break 
with the least handling. Even in their ordinary course of 
life the scales rub off, and with certain species an adult 
which is two or three weeks old is quite different in ap- 
pearance from one which has just emerged from the pupa. 
Practically, they can not be handled with the fingers, or 
their value as cabinet specimens or as specimens for study 
is lost. With some forms there are important charac- 
ters in the arrangement of the scales on the thorax. With 
others the scales on the wing are of importance and if 
the front legs are accidentally broken off, an important 
character to which I have referred in the systematic por- 
tion of this book as existing in the claws of the fore feet, 
is naturally unavailable. In capturing them, therefore, 
they must not be handled, and I have found the most sat- 
isfactory method of capture to consist in simply placing 
a small, open-mouthed vial over the mosquito while at 
220 HOW TO COLLECT MOSQUITOES 
221 
rest. On the wing it cannot be caught, even with a deli- 
cate net, without rubbing or leg-breaking. If a mosquito 
lights upon your hand, or upon a twig or a leaf, or upon 
a wall of a room, it is quite easy, especially if it be en- 
gaged in sucking blood, to cover it adroitly with the vial. 
It rises almost instantly, and the mouth of the vial is 
plugged with a plug of absorbent cotton. A drop of 
chloroform on the cotton will stupefy the specimen almost 
immediately and another drop will kill it. 
The specimen may be kept permanently in the vial and 
when studied, if the study goes no farther than an exami- 
nation of the coarser characters in an attempt to determine 
the species, it will often suffice gently to slide it out 
upon a sheet of white paper and examine it with a power- 
ful hand lens. With the one-quarter inch achromatic 
triplet lens made by different firms I have found it pos- 
sible to distinguish all of the generic and specific char- 
acters, even down to the teeth of the tarsal claws. This, 
however, is difficult to persons who are not accustomed 
to the use of liigh-power hand lenses, and in such in- 
stances one must break off a tarsus and mount it upon a 
slide in glycerine or Canada balsam for examination 
under a compound microscope. 
It is not advisable to mount adult mosquitoes bodily on 
slides in any medium whatever. They should not be pre- 
served in alcohol or formalin, but should be kept dry in 
vials. Of course they will rattle around somewhat and 
there is danger that the legs and the antennse will be lost; 
therefore, if they are moved from the vial after the col- 
lecting and killing, into pill boxes with cotton, they can 222 
MOSQUITOES 
be carried safely or can be sent in the mails. Several of 
the pill boxes may be placed inside a tight tin or wooden 
box and mailed with perfect security. 
A collection of mosquitoes should, however, not be kept 
in this way, provided it is intended as a study collection. 
The method which I have adopted and which is the 
one customarily used for small insects that are not too 
small for hand-lens work, is the triangular-tag method. 
Take a sheet of stiff paper or very thin cardboard and cut 
a strip, say, five-sixteenths or three-eighths of an inch 
wide. Then from this strip, by slightly oblique cuts, 
cut a series of triangles that will be pointed at the tip 
and a little less than an eighth of an inch wide at the 
base. Through the base of the tag may be run an insect 
pin and to the tip the mosquito should be glued, white or 
yellow shellac being the best medium for the gluing. The 
mosquito should be glued on its side, just behind one 
wing, so that its back is away from the pin. This enables 
one readily, by holding the point of the pin in his hand, 
to examine with a lens all legs, antenna), palpi, one side, 
and the back. The tag should be pushed up on the pin 
until it is from two-tliirds to three-quarters of the length 
of the pin away from the point. To the lower part of the 
pin should be attached a small label, giving date, exact 
locality, and name of the collector, and below this may be 
pinned another small label, bearing the name of the 
insect. 
Those who for some reason do not like the paper tri- 
angle method of mounting use very minute pins made by 
Muller in Vienna and known as “minuten insekten na- JIOW TO COLLECT MOSQUITOES 
223 
dein,” which are sold by Queen A Co., Philadelphia, 
and other large dealers in such things. These pins are 
so small and delicate that they may be thrust through 
the thorax of the mosquito and into a little strip of cork, 
the cork strip itself being pinned upon one of the larger 
and longer insect pins. 
Some collectors, instead of using the chloroform meth- 
od of killing, prefer the cyanide bottle. The cyanide 
bottle is made by taking a wide-mouthed flask, putting 
a small lump of cyanide of potassium at the bottom and 
covering it with a layer of liquid plaster of Paris, which, 
when allowed to set, makes a complete layer over and 
around the cyanide and prevents the water that comes 
from the deliquescence of the cyanide from injuring 
specimens that are placed in the vial, but which at the 
same time is sufficiently porous to permit the escape of 
the deadly cyanide fumes. Even with the layer of plas- 
ter of Paris, however, the cyanide bottle will sometimes 
become wet, so that a bit of blotting-paper may with 
advantage be inserted to cover the plaster of Paris, and 
to absorb the superfluous moisture. A mosquito capt- 
ured in one of these cyanide flasks or vials dies very 
quickly and is in good condition for dry mounting or for 
transfer to pill boxes. The cyanide bottle is preferably 
stoppered with a cork stopper, but rubber stoppers are 
also used. 
Ill collecting' early stages of mosquitoes it is only nec- 
essary to have a supply of bottles, a little coffee-strainer 
with a handle, and a large reading-glass. Other appar- 
atus is cumbersome and unnecessary. I have a large 224 
MOSQUITOES 
reading-glass four inches in diameter, with a strong han- 
dle, which I find very useful in examining the surface of 
water-pools, especially for Anopheles larvae. The dip- 
strainer used is an ordinary cheap coffee-strainer which 
has been mounted upon a long handle, so that one can 
reach out two or three feet from the shore and capture 
larvae and pupae. Other larger strainers with a fine mesh 
are sold at the hardware stores and may be purchased 
cheaply. In bringing larvae and pupae in from the field, 
too much jarring about in a bottle may result in their 
death by drowning. It is desirable, therefore, to put 
moss or water-weed in the bottle with a minimum of 
water, provided the insects are transferred to an aquarium 
or a still jar within a few hours. 
Nuttall, Cobbett, and Strangeways-Pigg, wlio liave done 
a great deal of collecting of mosquito larvae in England, 
as shown in one of their important papers, entitled 
“ Studies in Relation to Malaria,” published in the Jour- 
nal of Hygiene, vol. i., No. 1, January, 1901, used as their 
collecting apparatus some wide-moutlied bottles of me- 
dium size with cork stoppers ; a white enamelled dipper 
which, when required, can be tied with a piece of twine 
to a long bamboo rod; a small pipette with a rubber bulb 
and small vials containing dilute alcohol for the preser- 
vation of larvae which they did not wish to keep alive. 
They travelled over England on their collecting trips on 
bicycles. When the larvae or eggs were captured in the 
porcelain dippers they were removed with a pipette and 
put in bottles, which were half filled with water, wrapped 
in cloths, and attached to the bicycle frame. They found HOW TO COLLECT MOSQUITOES 
225 
that they could be transported for several hours without 
injury. They noted also that the large larvae did not 
withstand the shaking as well as the small ones, but that 
a sufficient number could always be brought back for 
studying purposes. On expeditions lasting a couple of 
days they took precaution to remove the corks occasion- 
ally to give the insects fresh air. White dippers were 
used, since they could more easily detect the eggs or 
larvae on the white background, and they found that only 
rarely could they detect the insects by direct inspection 
of the surface of the water. 
Larvae ancl pupae, when it is desirable to preserve them 
in these stages, and it is always desirable to keep a small 
set of each species, may be kept in vials of alcohol or di- 
lute formalin (5 to 10 per cent.). When preserved in alco- 
hol they should be passed through different strengths, 
beginning with a weak mixture, in order that they may 
not shrivel; or, what is still better, kill the larvae or pupae 
suddenly in a cyanide bottle, then bring the water nearly 
to the boiling point in a little porcelain dish over an alco- 
hol lamp and drop the insects in, leave them until the 
boiling point is just reached and then remove them. An 
immersion of only a few moments will suffice. Ordina- 
rily the larvae will sink at once to the bottom of the water 
and very soon thereafter rise to the top. This rising is 
an indication that the specimen should be removed at 
once. The specimen may then be preserved in ordinary 
commercial alcohol and will retain perfectly its color and 
shape. This method is used successfully with the larvae 
of many insects. It is not necessary to mount either 226 
MOSQUITOES 
larva) or pupae whole on slides. One of these preserved 
specimens can be put in a cell with alcohol or glycerine 
and studied under a low power with perfect ease, and the 
examination of minute details of its anatomy, external 
and internal, may readily be accomplished by dissection, 
and the parts dissected out mounted permanently on 
slides in any of the ordinary media. 
In rearing different species of mosquitoes I have had 
perfect success in the use of large, cylindrical glass jars 
known as battery jars. They can be bought in almost 
any city and of various sizes. The size which I find most 
convenient will hold about a gallon of water. A layer 
of sand an inch or two deep is placed in the bottom 
of the jar and a quart or more of water poured over it. 
After the sand has settled and the water has cleared, a bit 
of almost any small water-plant may be inserted to ad- 
vantage, provided mosquitoes of the genus Culex are be- 
ing reared. If the experiment is with Anopheles, how- 
ever, some fresh-water alga is introduced, such as 
Spirogyra, Mougeotia, QEdogonium, Cladophora, or Os- 
cillaria—almost any green scum from stagnant water, in 
fact. Over the top of the jar is placed a piece of swiss, 
or other fine, translucent cloth, held down by a large rub- 
ber band. 
The eggs of Culex may be had with ease by exposing 
a bucket of water out of doors in a mosquito locality on 
almost any summer night. If the egg masses be trans- 
ferred from the bucket to the prepared breeding-jar the 
growth of the larvae can be watched and their transfor- 
mations can be observed with perfect ease. Occasional HOW TO COLLECT MOSQUITOES 
227 
specimens can be taken out and preserved, to illustrate 
variations of different stages of growth. Accurate notes 
can be kept as to temperature, periods of transformation, 
and so on. A series of dates, provided several jars are 
under observation, can be written from time to time upon 
a slip of paper, which may be pinned to the edge of the 
cloth-covering of each jar. 
Where the eggs of Anopheles, for example, have not 
been found, females collected at large may be liberated 
in such a prepared breeding-jar. They will rest on the 
under side of the cloth-covering during the day and at 
night will lay their eggs on the surface of the water. It 
is desirable to have a stick in the water, or a leaf, or a bit 
of cork, floating on the surface. I have had no difficulty 
in obtaining the eggs of Anopheles in large numbers in 
this way and the eggs of Culex as well, but although as 
many as fifty females of Psorophora have been liberated 
in breeding-jars prepared in this way, I have not been 
able to get the eggs of this genus, which, as a matter of 
fact, are yet unknown. It is possible that Psorophora does 
not deposit its eggs upon the surface of water. This, 
however, is unlikely and it is rather to be supposed that 
the females used in my experiments were not old enough 
for oviposition and died from the confinement of the jar 
before the egg-laying period arrived. 
When one wishes to study closely the movements and 
intimate habits of the early stages of mosquitoes a great 
deal may be observed through the glass sides of the jar, 
by using a coarse lens and studying those near the edge. 
But when a closer study is desired, individual larvae or 228 
MOSQUITOES 
pupae may be lifted out with a strainer and put in a shal- 
low porcelain vessel where they can be watched with ease 
under a dissecting microscope. Anopheles larvae may be 
studied in this way very easily, and no nature study could 
be of more fascinating interest than the observation of 
these creatures, lying as they do with the body practi- 
cally in a single plane, so that they may be easily 
watched, with the mouth-parts in constant action, and 
the head occasionally turning upside down and the re- 
verse with lightning-like rapidity. CHAPTER X 
The Classification of the United States Mos- 
quitoes 
THE mosquitoes belong- to that order of insects known 
as the Diptera. The Diptera are the true flies. They 
possess but two wings, the second pair being repre- 
sented only by two little projections known as halteres or 
poisers. The mouth-parts are formed for sucking and the 
transformations are complete, that is to say, the early 
stages differ radically from the adult. In the order Diptera 
the mosquitoes are separated into a distinct family known 
as the Culicidae, the family name being derived from the 
name of the typical genus Culex (see Chapter III.), the 
generic name Culex being taken from the Latin word 
culex, which means a midge or a gnat. The true mos- 
quitoes of the family Culicidae are distinguished by hav- 
ing the antennae furnished Avitli whorls of hairs, which are 
very delicate and long in the male, and sparse in the 
female. The head is furnished with a long, projecting 
beak, which in the female is capable of piercing the skin 
of human beings. The wings are as a rule transparent, but 
to the veins, when seen under the compound microscope, 
are attached scales of different shapes, something like 
209 230 
MOSQUITOES 
the scales of a butterfly’s wing. The Culicidte that occur 
in the United States are divided into nine genera and 
about twenty-four recognized species. More species have 
been named, but some of them have been shown to be the 
same as others which were previously named, so they are 
included as synonyms. In the analytical tables which 
follow, the characters which distinguish these different 
genera and species are given. These tables have been 
drawn up by Mr. D. W. Coquillett, a well-known writer 
Fig. 48.—Claws of Front Feet of Culex stimulans; female at right, male 
at left greatly enlarged. (Original.) 
on insects of the order Diptera, who has made at my re- 
quest a study of the North American species of the 
family Culicidae. The tables have been made as plain 
and as non-technical as possible, but there are a few 
points which should perhaps be explained. In unrevised 
form, these tables appeared in the writer’s bulletin on 
mosquitoes, published in August, 1900, and I have no- 
ticed that some observers have found difficulty with 
the characters relating to the teeth of the tarsal claws C LASS IF 10 A TION OF TIIF MOSQUITOES 
231 
and to the one which is mentioned as the “ petiole of the 
first submarginal cell.” In order to study the teeth of 
the claws of the front feet, it is necessary for most people 
to break off a foot and mount it on a microscope slide, for 
study with the compound microscope. One who is keen- 
sighted and expert with the hand lens can make them out 
pretty well with a rather high power (say a quarter-inch 
Tolies triplet) hand lens, but many others have great diffi- 
Fig. 49.—Claws of Front Feet of Culex perturbans; female at right, male 
at left; greatly enlarged. (Original.) 
culty in detecting1 them in this way. This, curiously 
enough, is especially true of those skilled in the use of the 
compound microscope. The terminal claws of the front 
feet of nearly all mosquitoes possess good characters in 
the teeth, and in order that readers may know just what 
to look for, the claws of the front feet of two species are 
shown on the accompanying cuts, with the teeth plainly 
indicated. Whether a claw bears one tooth, or two, or 
none, is very important in the classification. 232 
MOSQUITOES 
The expression “ petiole of the first submarginal cell ” 
is, I realize, incomprehensible to anyone not familiar with 
the vocabulary of scientific entomology. Therefore on 
the accompanying cuts are indicated this first submarginal 
cell and its petiole. The petiole is the vein which runs 
from the end of the cell back 
to the first cross-vein, and 
the relative length of this 
petiole and of the cell it- 
self are of importance in 
the classification. 
The names used in this 
series of tables, and in this 
book, as a whole, differ in 
some slight degree from 
those which have been used 
in the previous writings of 
the author, and of Mr. Co- 
quillett. Gulex tceniatus, for 
example, a name which was 
used in Bulletin 25, has been 
decided to be a synonym of 
Stegomyia fasciata. In this 
conclusion Mr. Coqnillett is 
joined by Mr. Theobald, the 
English author. Gulex excitans of Bulletin 25, is stated by 
Mr. Theobald to be also a synonym of S. fasciata, from a 
study of the type specimen. Anopheles argyritarsis has 
been added, since, although it is not known to occur in 
the United States, it has been found in Cuba by the Army 
Fig. 50.—Wing of Culex conso- 
brinus (above) ; and C. pipiens 
(below); showing petiole of first 
subinarginal cell; enlarged. 
(Original.) CLASSIFICATION OF THE MOSQUITOES 
283 
Yellow-fever Commission, and is of some importance to 
us, as Cuba is so near our Southern States, and American 
citizens have so many interests in Cuba. Another species 
of Megarhinus, namely, grandiosa, Williston, has been 
added by Mr. Coquillett. 
It is unfortunate that this table has to be published be- 
fore the monographic work by Mr. F. Y. Theobald, the 
English expert, who has had exceptional advantages in 
his studies, for the British Museum, of the mosquitoes of 
the whole world, makes its appearance. From correspond- 
ence with Mr. Theobald I learn that his opinions differ in 
some respects from those of Mr. Coquillett in regard to the 
proper names for some of our mosquitoes. For example, 
the brownish, sordid mosquito which we called Culex 
pangens is, in Mr. Theobald’s opinion, composed of two 
distinct species, namely, Cidex pipiens (a common Euro- 
pean mosquito), and Cidex fatigans, an East Indian 
species which he says is identical with Culex pungens, and 
which he states occurs abundantly in many parts of the 
world, extending north and south of the Equator to about 
SS-1 north and south latitude (just about the range of the 
yellow-fever mosquito). Mr. Theobald is also inclined to 
think that the Culex impiger of Walker is identical with 
the species known to entomologists as Culex nigripes of 
Zetterstedt, and he also has a mosquito from North Amer- 
ica which he thinks is Cidex annulatus Meigen, a form 
which we have not recognized in the United States. Mr. 
Theobald has also received from Canada an Anopheles 
which he thinks is a variety of A. bifurcatus. This also 
is a species which is unknown to us in the United States. 234 
MOSQUITOES 
It will be noticed in the tables which follow, and in the 
consideration of mosquitoes and yellow fever in Chapter 
V. that Mr. Coquillett and the writer have adopted the 
generic name Stegomyia for the mosquito which has in 
our previous writings been named Culex fasciatus. I have 
been induced to adopt this name through correspondence 
with Mr. Theobald, who writes me that he has discovered 
characters which separate this mosquito from the old 
genus Culex, and that he has proposed the name Stego- 
myia for the genus. He has given me no clew as to the 
characters upon which he has founded this genus, except 
that they are “ scale characters.” A study of the scale 
structure of this insect and other mosquitoes of the genus 
Culex does not reveal any very important differences, but 
Mr. Coquillett, from other characters, has concluded to 
adopt Mr. Theobald’s generic name, and it is here used 
with the characters pointed out in the table. It will be 
unfortunate should this use of the name antedate the 
publication of Mr. Theobald’s monograph, since the genus 
should be his and not ours. Two other new generic names 
proposed by Mr. Theobald, viz.: Toxorliynchites and Con- 
chy Hastes, have been adopted and are characterized in the 
tables. It will be noticed that the characterizations are 
printed with quotation marks, and that they are followed 
by Mr. Theobald’s name in parenthesis. This method of 
printing will make Mr. Theobald responsible for these 
genera as well as for Stegomyia, in the event that this 
book is issued from the press in advance of his publica- 
tion. 
With these words of explanation, the following- tables, CLASSIFICATION OF THE MOSQUITOES 
235 
for which it must be distinctly understood Mr. Coquillett 
is responsible, and for which I owe him many thanks, will 
probably enable those who are at all in earnest in the 
matter to distinguish our species without great difficulty. 
I.—Generic Synopsis. 
The following table contains all the genera of the long-beaked 
mosquitoes known to occur in North America. The males are 
readily recognized by the antennae being densely covered with 
long hairs; in the females the hairs of the antennae are short 
and very sparse : 
1. Palpi in the male at least nearly as long as the proboscis ; in 
the female less than one-half as long 3 
Palpi in both sexes at least almost as long as the proboscis . 2 
Palpi in both sexes less than one-half as long as the pro- 
boscis 7 
2. Proboscis straight or nearly so, colors of body brown and yel- 
lowish Anopheles. 
Proboscis very strongly curved, colors bluish or greenish. 
Megarhinus. 
3. Legs bearing many nearly erect scales Psorophora. 
Legs destitute of such scales 4 
4. Colors, black, brown and yellowish, proboscis almost 
straight 5 
“Colors, green and bluish, proboscis very strongly curved ” 
(Theobald) Toxorhynchites. 
5. “Thorax marked with lines of silvery scales” (Theo- 
bald) Stegomyia. 
Thorax not marked in this way G 
6. “ Hind feet black, their apices snow white” (Theo- 
bald) Conchyliastes. 
Hind feet not marked like this Culex. 
7. Upper side of thorax with line of bluish scales.. Uranotamia. 
Upper side of thorax not marked in this way Aedes. 23G 
MOSQUITOES 
II. Genus Uranot^enia. 
Our single species is rarely met with ; it is among the smallest 
of mosquitoes and will readily be recognized by the stripe of vio- 
let-blue scales on the thorax : 
sapphirina O. S. 
III. Genus Aedes. 
The single species is likewise rarely met with, and like the 
preceding, is of very small size ; it is of a brownish color with 
golden-yellow scales on the thorax and cross-bands of white ones 
on the abdomen : 
fuscus O. S. 
IV. Genus Conchyuiastes. 
Our two species are of medium size and of rather rare occur- 
rence ; they may be distinguished as follows : 
With the last two joints of the hind feet white musicus Say. 
With only the last joint of the hind feet white, .posticatus Wied. 
V. Genus Stegomyia. 
Our two species are of rather small size, and may be distin- 
guished by the following characters : 
Front claws of the female toothed on the under side, the 
outer silvery stripes of the thorax greatly widened in 
front of the wings fasciata Fabr. 
Front claws not toothed, the outer silvery stripes of the thor- 
ax very narrow throughout their entire course.signifera Coq. 
fasciata Fabr. 
excitans Walk. 
frater Desv. 
mosquito Desv. 
tceniatus Wied. 
signifera Coq. CLASSIFICATION OF THE MOSQUITOES 
237 
VI.—Genus Culex. 
(a) RECOGNIZED SPECIES. 
Males. 
1. Front tarsal claws bearing a distinct tooth near the middle of 
the under side of each 3 
Front tarsal claws bearing two teeth on the under side of one 
claw, and one on under side of the other, proboscis destitute 
of a whitish band near the middle 2 
2. Feet distinctly white at bases of the joints . sollicitans Walk. 
Feet not white at bases of the joints consobrinus Desv. 
3. Proboscis destitute of a whitish ring near the middle 4 
Proboscis with such a ring, ends of tarsal joints white 
tarsalis Coq. 
4. Bases of tarsal joints not white 5 
Bases of tarsal joints white stimulans Walk. 
5. Palpi not dilated 0 
Palpi strongly dilated toward the apex impiger Walk. 
6. Petiole of first submarginal cell at most one-fourth the length 
of that cell pipiens Linne. 
Petiole at least almost half as long as the cell. pungens Wied. 
Females. 
1. Front tarsal claws bearing a distinct tootli near middle of 
under side of each 2 
Front tarsal claws destitute of teeth 7 
2. Proboscis destitute of a white ring near the middle 4 
Proboscis marked with such a ring, bases of tarsal joints 
white 3 
3. With a stripe of yellowish scales in middle of the abdo- 
men sollicitans Walk. 
Without such a stripe tceniorhynchus Wied. 
4. Bases of tarsal joints distinctly white stimulans Walk. 
Bases of tarsal joints never white 5 238 
MOSQUITOES 
5. Abdomen marked with a cross-band of whitish scales at 
base of each segment impiger Walk. 
6. Abdomen never marked in this manner, but with a cluster 
of whitish scales at front angles of some of the seg- 
ments triseriatus Say. 
7. Proboscis marked with a distinct whitish ring near the 
middle, feet white at sutures of the joints 8 
Proboscis destitute of a whitish ring near the middle 9 
8. Tarsal joints white at bases only perturbans Walk. 
Tarsal joints white at both ends tarsalis Coq. 
9. Feet white at bases of joints : excrucians Walk. 
Feet never white at bases of the joints 10 
10. Petiole of first submarginal cell about one-eighth the 
length of that cell pipiens Linne. 
Petiole one-fourth the length of that cell.. . pungens Wied. 
Petiole at least almost half the length of that cell. 
consobrinus Desv. 
annulatus Schrank. This European species was credited to 
our fauna by Osten Sacken. 
boscii Desv. Probably a rubbed specimen of pungens. 
nigripes Zett. Black, the legs of the male dark yellow, hairs 
of pleura of female gray, a band of white scales at base of each 
segment of her abdomen. 
rubidus Desv. The description was apparently founded on a 
rubbed specimen of Psorophora ciliata. 
testaceus v. d. Wulp. Must closely resemble consobrinus. 
incidens Thomson. Is evidently a synonym of impiger 
Walker. 
bigoti Bellardi. According to the figure and description, the 
bands of black scales are at the bases of the abdominal seg- 
ments; in the recognized species these bands are always at the 
apices of the segments. In other respects this species must greatly 
resemble pungens. 
cubensis Bigot. Apparently founded on a badly rubbed speci- 
men of pungens. 
(b) UNRECOGNIZED SPECIES. CLASSIFICATION OF THE MOSQUITOES 
239 
frater Desv. This name was proposed for the Culex fasciatus 
of Wiedemann, under the impression that this is not the same 
species as the one described by Fabricius under the same name. It 
seems quite certain, however, that the word “proboscis” in Fa- 
bricius’s description was simply a lapsus for “ palpi,” and with 
this emendation the two descriptions agree very well. 
mexicanus Bellardi. Is evidently a synonym of posticatus. 
pipiens Linne. A European species recently reported by 
Mr. Theobald as occurring in this country. 
promeans Walker. Is a synonym of nemorosus Meig., accord- 
ing to Theobald. 
territans Walker. Is apparently related to pungens. 
Our recognized species of Culex and their synonyms may be 
listed as follows, the synonyms indented : 
consobrinus Desv. 
? annulimanus v. d. 
Wnlp (Anopheles). 
impatiens Walker. 
inornatus Williston. 
pinguis Walker. 
1 runctor Kirby. 
impiger Walker. 
implacabilis Walker. 
incidens Thomson. 
? quinquefasciatus Say. 
perturbans Walker. 
pipiens Linne. 
pungens Wied. 
? boscii I)esv. 
? eubensis Bigot. 
? fatigans Wied. 
stimulans Walker. 
tceniorhynchus Wied. 
damnosus Say. 
sollicitans Walker. 
tarsalis Coquillett. 
triseriatus Say. 
VII.—Genus Psorophora. 
Our single species is of a yellowish color, usually varied with 
brown, the bases of the tarsal joints white. It is considerably 
larger than any of our other species of yellowish or brown mos- 
quitoes : 
ciliatus Fabr. 
molestus Wied. 
? rubidus Desv. 240 
MOSQUITOES 
VIII.—Genus Toxorhynchites. 
These are among the largest of our mosquitoes, and closely re- 
semble those of the following genus. Our single species has all 
of the feet marked with white : 
rut Hus Coq, 
IX.—Genus Megarhinus. 
Our three species are among the largest in this family, and are 
not known to occur north of the District of Columbia. They 
may be separated as follows : 
Hind feet alone marked with white 1 
None of the feet marked with white hcemorrhoidalis Fabr. 
1. Front and middle feet wholly black portoricensis Roeder. 
Front arid middle feet yellow, first joint of the front ones 
black * grandiosa Will. 
X.—Genus Anopheles. 
(a) RECOGNIZED SPECIES. 
1. With a yellowish white spot near three-fourths the length of 
the front margin of the wing 3 
Witliout such a spot 2 
2. Scales of last vein wholly black, palpi wholly black 
maculipennis Meig. 
Scales of last vein white, marked with three black spots, palpi 
marked with white at bases of last four joints, crucians Wied. 
3. Hind feet wholly brown, scales of last vein white, those at 
each end black punctipennis Say. 
Hind feet largely snow-white on the apical half. 
argyritarsis Desv. 
* This species, of which I have never seen a specimen, probably be- 
longs to the preceding genus.—D. W. C. CLASSIFICATION OF THE MOSQUITOES 
241 
(b) UNRECOGNIZED SPECIES. 
The following species which have been credited to our country 
have not been recognized with certainty ; some of them probably 
do not belong to the present genus, while a few were evidently 
founded on badly rubbed specimens in which the distinctive 
characters were therefore wanting : 
annulimanus v. d. Wulp. I strongly suspect that this does 
not belong to the present genus; the description applies fairly 
well to the male of Culex consobrinus Desv. 
ferruginosus Wied. This name was proposed for the species 
previously described by Say under the name of Culex quinque- 
fasciatus, but the description differs so decidedly from the one 
published by Say as to give the impression that it is founded on 
a different species. I strongly suspect that the type of ferrugi- 
nosus is a rubbed example of Anopheles crucians, which was de- 
scribed from the same locality. Say’s description of his Culex 
quinquefasciatus agrees very well with the species which I have 
identified as Culex impiger Walker. 
maculipennis Meigen. According to Theobald this European 
form is identical with our Anopheles quadrimaculatus Say. 
nigripes Staeger. This European species should be readily 
recognized by its unspotted wings. 
albimanus Wied. Differs from our other species by the snow- 
white apices of the tarsi. 
pictus Loew. Is evidently closely related to crucians Wied. 
Our recognized species of Anopheles and their synonyms may 
therefore be listed as follows, the synonyms indented : 
argyritarsis Desv. 
crucians Wied. 
? ferruginosus Wied. 
maculipennis Meigen. 
quadrimaculatus Say. 
punctipennis Say. 
hiemalis Fitch.