APR 24 1399 Mr Plfitr .5 Filch. Del / \ .r. K.Gsv,! s. Engraa rd'forth,. Xmmwi l>itarMy Journal of. {prmi/turr From the Transactions of the New-York State Agricultural Society, Vol. v., 1845. AN ESSAY UPON THE WHEAT-FLY, AND SOME SPECIES ALLIED TO IT. -A By ASA FITCH, M. D. ____________I JjA 1>JK,* Vi v » ! rtr i i v.* rjuJ ALBANY: | ^X PRINTED BY C. VAN BENTHUYSEN AND CO. 1846. " THESE SMALL INSECTS ARE THE WHEAT CROP'S GREATEST ENEMY."--Gullet. THE WHEAT-FLY* Although several facts in the habits and economy of the wheat-fly had occurred to my notice at sundry times since its appearance in this vicinity, yet as my leisure for studies of this nature was wholly engrossed in other departments of the science of entomology, these facts had been observed in too cursory a manner to be of material value in preparing an account for the public eye. It has not been until the present year, that I have made this and its allied species my particular study. And as some few interesting points still remain undetermined, ere a perfectly complete history of this insect can be given, I should be inclined still to defer preparing a paper upon this subject, but that I deem some of the observations already made of too much importance to be longer withheld, and am moreover very well aware that if no writer ventured to appear before the public until his investigations were so complete in every particular that he could exhaust the subject on which he wrote, very little would be published, and the world would have but a small fraction of that amount of information which it now possesses. It is necessary for me further to premise, that although we have two distinct species of wheat-flies, as will be fully shown in the sequel of this paper, to wit, the clear-winged wheat-fly (Cecidomyia Tritici of Kirby) and the spotted-winged wheat-fly, which has hitherto remained a nondescript; yet as nothing is yet known of the habits and transformations of one of these as distinct from the other, through the body of this article the common name " wheat-fly" will be em- ployed for convenience as referring to both these species. Future researches, however, may detect dissimilarities in their habits, and show that portions of the following account are true only with regard to One of these. • The following essay originally appeared in the American Quarterly Journal of Agriculture and Science, vol. ii, number 2; to the editors of which our acknowledg- ments are also due for the illustration with which it is accompanied. The essay has been revised, and new paragraphs added by the author. 4 Its Foreign History. The first distinct and unequivocal account of the wheat-fly, of which I am aware, is that given by Mr. Christopher Gullet, in 1771, in a letter to Dr. Matty " On the effects of elder in preserving growing plants from the insects and flies," which letter was published in the Philosophical Transactions of the Royal Society the following year.* * So long ago as the year 1768, Col. Langdon Carter, of Virginia, transmitted to the American Philosophical Society a paper entitled " Observations concerning the fly- WEEVil that destroys the wheat;" which was published in the first volume of the So- ciety's Transactions, 2d edition, pages274-287. The account here given, is in nearly all its particulars so strikingly applicable to the wheat-fly, that so much of it as relates to the insect itself merits an introduction in this place. He rather quaintly remarks, " In a pleasant evening, after the sun was down, and every thing serenely calm, I found the rascals extremely busy amongst my ears, and really very numerous. I immediately in- closed some of them in a light loose handkerchief; and by the magnifiers of my tele- scope, I took occasion minutely to examine them. They area pale brownish moth, with little trunks or bodies, some trifle shorter than their wings; and as some of their little bodies appeared bulging as if loaded; I applied the pressure of a fine straw upon them, and saw them squirt out, one after another, a number of little things which I took to be eggs, some more, some less: some emitted fifteen or twenty of them- and others appeared extremely lank in their little trunks, which I could not make dis- charge anything like an egg. Whether they had done this in the field before, or were of the male kind, I could not tell; but from this discovery I concluded that there need not be above two or three flies to an ear of corn, to lay eggs enough to destroy the greatest crop. * * * It is with much propriety called a weevil, as it de- stroys the wheat even in our granaries; though it is not of the kind termed by natu- ralists the curculio. of which they have given a very long list; for it is not like a bun- it carries no cases for its wings; neither has it any feelers, with which the curculio is always distinguished; and perhaps (as I fancy it will turn out in the course of this letter that they never attack grain when hard) they really have no occasion for such feelers. For from the make of it, to my judgment, it appears an impossibility that it should ever perforate into a hard grain, being furnished with nothing in nature, from the most minute examination by glasses, that could make such a perforation; and seems indeed a fly itself, consisting of nothing sensible to the slightest touch with the finger, nor to the eye assisted with glasses, leaving only a little dry pale brown glossy dust on being squeezed." I doubt not but that on perusing this extract, almost every reader who is conversant with our wheat-fly, which also is so frequently called "the weevil," will feel confi- dent that it is the same insect to which Col. Carter alludes. Yet if his account be more particularly observed, we gather from it some characters which assure us that it was not the wheat-fly which he examined. Although he uses the terms moth and fly as synonymous, and no where tells us whether his specimens had four or only two wings, yet he couUl scarcely have spoken of the lively orange color of our wheat-fly as pale brownish ;> and what is yet more conclusive, his insect, on being pressed ^1 o T' ^f ledryPalebr°Wn **•***.» whereas the wheat- fly leaves no mark upon the fingers, unless it be actually crushed, in which case its 5 From this it would appear that the effects produced by the wheat-fly had been known for some time to the farmers of England, though imputed by them to a wrong cause. He says, " What the farmers call the yellows in wheat, and which they consider as a kind of mildew, is in fact occasioned by a small yellow fly with blue wings, about the size of a gnat. This blows in the ear of the corn, and produces a worm, almost invisible to the naked eye ; but being seen through a pocket microscope, it appears a large yellow maggot, of the color and gloss of amber, and is so prolific that I last week dis- tinctly counted forty-one living yellow maggots in the husk of one single grain of wheat—a number sufficient to eat up and destroy the corn in a whole ear. * * * One of these yellow flies laid at least eight or ten eggs of an oblong shape on my thumb, only while carrying by the wing across three or four ridges." It was several years subsequent to this date, that the accounts of the appalling ravages of the Hessian fly among the wheat crops of America reached Europe ; and as this fly was universally believed to have been derived from the old world, extensive and careful exami- nations of the grain fields there were made to detect it, that its habits might he learned, and means devised for preventing its becoming such a scourge as it was to this country. These investigations, con- ducted often at the public expense, and by men whose acquirements peculiarly fitted them for such a work, resulted in a confident an- nouncement, which received general credence for a long series of years, that the Hessian fly did not exist in Europe ; yet in their course, several other species of insects injurious to the cultivated grains of that continent were discovered, and the wheat-fly received a particular examination. Mr. Curtis, generally so accurate in his statements, says that it was first discovered at this time ; but the ac- count already given from Mr. Gullet, shows that it was known in England at least twenty-five years earlier than Mr. C. supposes, and fluid juices produce a yellow stain, without any glossiness. Every one accustomed to the handling of insects, will at once recognize the character in question as applying admirably to some small species of moth; and the " Committee on Husbandry" of the Society, in their remarks at the close of Col. Carter's paper, are doubtless correct in their statement, that these insects " appear to be of the same kind with those that do the like mischief in Europe, which a gentleman of Angumois describes to Mr. Du- hamel," and which have since become so well known as the "Augnmois grain-moth," described by the naturalist Olivier under the technical name of Alucita cerealella. 6 anterior even to the date when the Hessian fly was first observed in America. In 1795, as we are informed by Mr. Marsham, in a paper read be- fore the Linnaean Society, London, and published in their Transac- tions, vol. iii. p. 142, towards the end of July, Mr. Long had observed an insect that threatened to do much mischief to the wheat crops, attacking one or more of the grains in an ear, and causing the chaff of these grains to become yellow or ripe, whilst the remainder of the head was still green. Mr. Marsham, on opening the chaff of these grains, found an orange-colored powder, and in many of them one or two very minute yellowish-white or deep yellow larvae, the grain it- self appearing to be a little shrunk. Mr. Markwick, of Sussex, also observed the same larvae in his wheat, the forepart of August, but was confident they had done no injury to it. The same larvae were also noticed by Mr. Kirby, this year, in Suffolk. In a subsequent paper from Mr. Marsham [Trans. Lin. Soc. vol. iv. p. 224), we are informed that Mr. Markwick, July 12,1797, saw fhe flies themselves, at rest upon the heads of the wheat, and also a few of the larva? within the flowers ; and that awhile later in the sea- son the fly appeared reduced in numbers, whilst the larvae had be- come much more abundant. From heads of the wheat enclosed in a flowerpot, he reared the fly, and also its parasite ; the fly thus ob- tained having " spotted wings," a fact which we shall revert to here- after. Following this account is an excellent article (p. 230) by the Rev. William Kirby, who has since become so well known by his various writings upon entomology. Mr. Kirby here gives a scientific de- scription of the wheat-fly, bestowing upon it the specific name tritici, by which it has been definitely distinguished by all subsequent wri- ters, and correctly referring it to the genus Tipula of Linnaeus, a genus which, in consequence of the vast number of species afterwards discovered to be comprised under it, naturalists have since found it necessary to subdivide ; and the species in question at this day falls within that group to which the name Cecidomyia was given by La- treille—an arrangement concurred in by Mr. Kirby himself in his communication in Loudon's Magazine of Natural History, vol. i. p. 227; and which I note thus particularly, as by most writers in our 7 Agricultural papers it is still spoken of as solely the Tipula Tritici of Mr. Kirby. In this article, and another presented about a year afterwards, {Trans. Lin. Soc. vol. v. p. 96), Mr. Kirby gives a large number of most interesting and valuable observations upon this insect, the cor- rectness of which, generally^ more recent investigations have fully attested,. With regard to its abundance at that time, he says he could scarcely pass through a wheat field, in which some florets of every ear were not inhabited by the larvae ; and in a field of fifteen acres, which he carefully examined, he calculated that the havoc done by them would amount to five combs (twenty bushels). From this time we have met with no notices of the wheat-fly} ex- cept occasional references to the articles above mentioned, until the year 1828, when, and for a few of the following years, it again ap- peared in such numbers and with such havoc in several of the coun" ties of England and Scotland, as to elicit communications in the magazines from several writers. In some districts of Scotland, its devastations would seeiuJ|to have approached in severity what has been experienced upon this side of the Atlantic ; for " Mr. Gorrie estimates the loss sustained by the farming interest in the Carse of Gowrie (the rich alluvial district along the Isla and its tributaries in Perth and Forfarshire) by the wheat-fly alone, at 20,000/. in 1827, at 30,000/. in 1828, and at 36,000/. in 1829" {Encyc. ofAg. 3d Lond. ed. p. 820. § 5066). And Mr. Bell, writing from Perthshire, June 24j 1830, says, u We are anxious to have the present cold weather conj tinue for another ten days, to prevent the eggs from hatching, until the wheat be sufficiently hardened and beyond the state which affords nourishment to the maggot. Another year or two of the wheat-fly will make two-thirds of the farmers here bankrupts," {Gardener's Magazine, vol. vi. p. 495). Mr. Gorrie, in a letter dated at Annat Gardens, Errol, Perthshire, Sept. 1828, {Loudon's Mag. of Nat* Hid. vol. ii. p. 292), solicits information " on the nature and mode of propagation of a fly which has this year destroyed about one-third of the late sown wheat all over this country." He describes a small yellow caterpillar, one-eighth of an inch long, as numerous in the young ears of wheat, completely devouring the young milky grain, becoming torpid in about twelve days, and in six days more chang- ing to a small black fly. In a subsequent communication, August 8 1829 (p. 323), he corrects the latter part of the above statement, and says, " At that time I did not know that a yellow fly had deposited the eggs within the glume, which became maggots. Observing numbers of black flies on the ears of wheat, I believed they had been the produce of the caterpillar. I have this season, however, observ- ed the yellow fly (described by Rev. W. Kirby) deposit its eggs in the wheat-ear," etc. I notice this more particularly, because the farmers in this vicinity, with scarcely an exception, have fallen into the same error, and to this day suppose a small black fly, of the fam- ily Muscidte, which occurs abundantly in wheat-fields, to be the real wheat-fly. Mr. Patrick Shirreff, of East-Lothian, gives, in the same volume of Loudon's Magazine, pages 448 - 451, an excellent and very accu- rate summary of the habits and transformations of the same insect, the result chiefly of his own observations. For a concise account,. this is not surpassed by any that has fallen under my notice. Still more recently, this subject has been investigated by the Rev, J. S. S. Henslow, Prof, of Botany in the University of Cambridge, whose valuable " Report on the diseases of wrheat" forms the first article in vol. ii. of the Journal of the Royal Agricultural Society of England. And in the same Journal for the present year (vol. vi. p. 131. plate M.) an admirable production is inserted from the pen and graver of that accomplished naturalist, John Curtis, F. L. S., giving much more accurate and precise descriptions and delineations of the , wheat-fly, in the different stages of its existence, than any that had previously appeared. To it I am particularly indebted for such characters as enable me to say without a doubt, that the clear-winged wheat-fly of America is identical with the English Cecidomyia Tri- tici. In closing this summary of the notices of the wheat-fly abroad, I would allude to what has occurred to me as perhaps true in the his- tory of this insect, to wit, that it has somewhat regular periods of re- curring in such numbers as to become a pest to the agriculturist. Thus, it is manifest from Mr. Gullet's account that it was abundant for a few years previous to 1771. So destructive was it then, that he pronounces " these small insects—the wheat crop's greatest ene- my." After an interval of twenty-five years, it is again observed plentifully for three or four years, and in different districts, by Messrs. 9 Kirby, Markwick and Long. Again it ceases to elicit attention, vn- til a period but a little longer elapses, when, in 1828 and the follow- ing years, it forces itself once more and still more prominently into notice. All that I design, is to direct attention to this point: the facts are as yet too few and too vague to justify anything more than a suggestion. The observations of Mr. Kirby, reaching now over half a century, could probably shed some light upon this most inte- resting topic. As respects the extent of its range abroad, it has been noticed in most of the southern and eastern counties of England, from Cornwall to Norfolk, and also in Shropshire ; in Perthshire and the Lothians, and probably in other districts of Scotland ; and in the north of Ire land. Whether it occurs upon the continent of Europe, we are not positively informed. It is not noticed by Macquart, either in his Diptera of the North of France, or his Natural History of Dipterous Insects (for a perusal of which I am indebted to the courtesy of Dr. T. W. Harris of Harvard University ;) and we can scarcely believe that if it existed in his district, it could have been overlooked by so assiduous a naturalist. M. Herpin, however (as we are told by Mr. Curtis,) is of opinion that it is an inhabitant of France, and the state- ment which he makes strongly supports this opinion. He says, " I have also found in ears of corn, at the time of flowering, many little yellow larvae, very lively, from two to three millimetres long, lodged between the chaff of the grain : these larvae nibble and destroy the generative organs of the plant, and the germen where they are found are sterile. These larvae appear to me to have a very great analogy with those which have been described in Linnaean Transa:tions, un- der the name of Tipula Tritici : it is probably a Cecidomyia." M. Herpin placed several ears of diseased barley and wheat in bottles, and in these bottles a number of Cecidomyia flies were afterwards found. Meigen—a copy of whose noted work upon the Diptera of Europe I regret that I have been unable to meet with—as I learn from Mr. Curtis's paper, gives descriptions and figures of the wheat • fly. Were his specimens collected in Germany, or received from England 1 10 ITS DOMESTIC HISTORY. It will be unnecessary to particularly specify the various notices of this insect, that have appeared in the different agricultural papers of the Northern States during the last twelve years. The more impor- tant and valuable of these may be found in the several volumes of the Cultivator and of the New-England Farmer. An excellent sum- mary of the history and habits of the wheat-fly, both in this country and abroad, is also given in Dr. Harris's Report on the Insects of Massachusetts, p. 437^44. Mr. Gaylord's paper on injurious in- sects briefly notices this species {Trans. JV*. Y. State Agric. Society, 1843, vol. iii. p. 145-147.) With the prominent facts that have been laid before the public by our agricultural periodicals, every intelligent farmer is already fa- miliar. The great difficulty experienced by persons but little conver- sant with zoological science, in determining what this wheat-worm really was, forms a striking feature in the earlier notices that appeared respecting it. Thus, by some it was for a time regarded as an animal- cula of the vibrio genus, analogous to the "eels" generated in vinegar and paste. By others, and quite extensively, it was pronounced to be a weevil, and this very improper name is to this day often applied to it. Others, still, deemed it to be "Monsieur Tonson come again," considering it as a return of the Hessian fly to a section of the coun- try from which it had long been absent. It would be easy to point out how erroneous each of these opinions are ; but I deem it wholly un- necessary, as the public mind is now no longer distracted upon this subject; and the correct view, that this insect is a fly, peculiar in its habits, and differing from any of those previously known in this country, universally prevails. It is not improbable but that one or both of the species of the wheat- fly may have been present in this country, in limited numbers, many years before it was distinctly noticed. In truth, common as this in- sect still is in this district, if our farmers, guided by the knowledge they have acquired of it, were not zealously searching for it in every field, I much doubt whether it would be at all observed here at the present day. And often too when a careful examination of the grow- ing grain leads to a belief that the crop is scarcely infested, an in- spection of the threshing-floor, or of the screenings of the fanning- 11 mill, will frequently demonstrate that it was present in much greater abundance than was surmised. These facts plainly show, that this insect might lurk a long time in our country wholly unobserved. Mr. Jewett says the wheat-fly first appeared in western Vermont in the year 1820, {New Eng. Farmer, vol. xix. p. 301.) It was not, however, till the years 1828 and 1829 that it became so numerous as to attract the attention of community ; the same years, be it observed, when its ravages were so annoying in Scotland. It was in the north- ern part of Vermont, bordering upon the line of Lower Canada, where it became so excessively multiplied at this time ; and from that, as a central point, it seems to have extended in nearly all directions. In this vicinity, one hundred and twenty-five or fifty miles south of the locality above indicated, it was certainly observed in 1830 ; and in 1832 the wheat crops were so completely destroyed by it, as to lead to a general abandonment of the cultivation of this grain. This was the year in which the malignant cholera swept over our land, and it was a common remark, that what the pestilence spared famine bade fair to destroy. Having spread east over Vermont and New-Hampshire, it in 1834 appeared in the State of Maine, and con- tinued to advance in that direction, it is said, at the rate of twenty or thirty miles a year. Westward its progress would seem to have been less rapid, and along the Mohawk river by no means so generally destructive. It is not till within a year or two past, that it has ap- peared in the Black river country east of Lake Ontario, as I am in- formed by an intelligent gentleman resident there; nor until the pre- sent season that it has been so injurious as to induce in some instan- ces a premature mowing of the crop, and preserving it for hay. Ru- mor states that farther west, in the wheat-noted Genesee country, it has been detected for the first time the present year. The amount of injury inflicted by this insect will be more distinctly and vividly realized, if we can arrive at some approximation to the sums of money that have been lost to certain districts in consequence of its presence. The Maine Farmer, vol. xiv. No. 2, states that " a million of dollars, nay, more money, would not pay the damage it has done to the state of Maine, alone." Half of that sum, it is probable, would not repay the loss which has been sustained merely in Washing- ton county, N. Y.—a county embracing (the unfilled mountain district bordering upon Lake George being deducted,) a population of about 12 35,000 souls, and an area of 700 square miles, of which nearly 500 are cleared and improved. Lest this statement should be deemed extravagant by the reader, I will adduce the data on which it is founded. When it is considered that the entire crop of 1832 was almost totally destroyed—that the crop of the previous year was much injured, and that for several of the sub- sequent ye,ars the man was deemed fortunate who received but half of a fair yield per acre—many obtaining back but little more than the amount of seed which they committed to the ground. I say, when these facts are duly considered, I think it will be regarded as but a moderate estimate if we set down the total amount of loss during the fourteen past years, as equal to the entire crops of three years, under ordinary circumstances. Had the usual quantity of land'been all along sowed with wheat, the loss would doubtless have been double that which we here are supposing it to have been. What, then, was the amount of the ordinary wheat crops in this country, formerly 1 No statistics, that I am aware, were then taken, by which this point can be definitely ascertained. But in 1844—the crop of which year is com- monly supposed to have been about a third or a fourth less than what was required for the consumption of the country—according to the census returns, 75,500 bushels were produced. Now, since the county formerly not only supplied its own wants, but transmitted a considerable surplus annually to market, it is probable that the yearly crop previous to the appearance of the wheat-fly, was twice or thrice what it amounted to in 1844, which would be from 150 to 200,000 bushels, the value of which for three years, gives us the sum first stated, half a million of dollars. And this estimate, be it observed, only contemplates the grain that has been destroyed, without taking into consideration the detriment that has been indirectly sustained by our farmers in being driven to a cultivation of those coarser grains which have yielded them a much less profit. The adjoining counties of Rensselaer and Saratoga, and the five western counties of Vermont, constituting the district over which this fly first swept and where perhaps its ravages have been most severe have probably suffered in about an equal degree with Washington county. Together they embrace an area about six times greater than that of Washington county. The whole of this district is therefore about equal in extent to the State of Connecticut, and the amount of 13 loss from the wheat-fly, upon the data above indicated, may be set down at three and a half millions of dollars! The history of the career of this insect, appears to be quite uniform in most of the districts hitherto visited by it. About two or three years after its first arrival at a particular locality, it becomes most excessively multiplied, and the devastations which it now commits are almost incredible. Though I believe that, through unduly excited fears, or a hope of thereby destroying hosts of this marauder, a mowing of the crop whilst yet green and a curing of it for hay has often been resorted to, when, had it been harvested as usual, a less sacrifice would have been made—yet many cases have occurred in which diligent search by different persons has failed to discover a single developed kernel of grain in any of the heads of an entire field! This havoc, so extreme and general, though not universal (for some fields even now escape with comparatively little injury,) lasts but a few years. The numbers of the pest and its consequent ravages soon become sensibly diminished ; and after the lapse of some seasons, the cultivation of the wheat crop is again found to be comparatively safe, and its yield only in isolated instances materially lessened by the con- tinued presence of the fly, which has now become probably a perma- nent inhabitant. It is now commonly supposed that this rapid diminution in the num- bers of the wheat fly has been produced by the general abandonment of the cultivation of wheat in this section of the country ; that thus the insect, having no place to deposit its eggs where its young could be nourished, has become measurably " starved out." But that this opinion is erroneous, is I think evident from one or two facts. During this entire period, since notice was first attracted to the wheat-fly, there are some farmers who have every year continued the cultivation of wheat with very fair success, their crops having been in no one of these years so severely injured as to dishearten them ; and their respective situations are so dissimilar, that this immunity can with no plausibility be attributed to any peculiarity in the location of their farms. Now if the swrarms of these insects which for a time pervaded every neighbor- hood through this entire section of country, and which possess a power of wing capable of bearing them from twenty to fifty miles in a single season, had been in the "starving" condition supposed, how have the fields alluded to escaped destruction'? Certainly these myriads of tiny 14 creatures could not have been reduced to such straits for want of the appropriate repository for their eggs, until after these crops have been utterly consumed. And, with the insect not exterminated, but still everywhere common, now that the culture of wheat has been gradually returned to with such success that it has again become general, why has not the fly again increased'? Why have the considerable crops of the past and the abundant ones of the present year (1845) in this county, been so little injured"? I am firmly persuaded, therefore, that the speedy diminution in the numbers of the wheat-fly, which soon follows a season in which it has been extremely annoying, can not be truly assigned to the cause above stated; but that it is rather to be attributed to that beautiful provision of nature long since observed, and additional instances of which are brought to light by the investigations of every year, to wit, that an undue increase in any of the species of the animal or vegetable world never takes place, without being speedily succeeded by a corresponding increase of the natural enemies and destroyers of that species, whereby it again becomes reduced to its appropriate bounds. Whenever once introduced, it is probable the wTheat-fly will ever after continue in limited numbers, laying the wheat crop annually under a moderate contribution for its support. Isolated fields will occur where its devastations will be quite serious, whilst the crop of the district generally will suffer but little, and many fields none at all. Such has appeared to be its history in this vicinity for several years past. Seasons favorable for its multiplication will doubtless occur, when its injuries will be much augmented; as well as seasons of a reverse character, when its presence will scarcely be known. It is therefore very important that the entire history and habits of this insect should be accurately traced out. For only with a full knowledge of these, can we be able to resort intelligently to such measures as will keep its numbers constantly limited, or sweep it from those fields that will probably at times be excessively infested by it. Its habits. Relying upon the correctness of the published statements, that it was not till "towards the last of June " that the fly infests the wheat- fields, and that the "principal deposit of eggs is made in the first half of July," I had not commenced searching for it, when on the 15 16th of June I was informed by a neighbor, that it had been present for some days in large numbers, in a field of thrifty winter wheat of his. Upon repairing to this field, a small black fly, about one-third of the size and much resembling the common house-fly, was pointed out as the dreaded enemy; and so universally has this doubtless harmless species been for years regarded as the true wheat fly by the farmers throughout this whole section of the "infected district," merely from the circumstance of its occurring abundantly in wdieat fields simultane- ously with the wheat-worm, that my companion was much surprised, and disposed to be incredulous of my assertion that that was not the wheat-fiy. On opening the flowers of wheat, however, the eggs of the real marauder were found in abundance; and a sweeping, with the small gauze fly-net in common use by entomologists, between the stalks of grain towards their roots, immediately caught within it a number of the winged insects. My comrade was little less surprised on my pointing the real fly out to him, being scarcely able to conceive that such a tiny fragile atom, seemingly a mere moat floating before his eye, could be that potent enemy that had spread such desolation over our land. Several of the specimens thus caught, were of the spotted- winged species. These I conjectured, until I afterwards came to examine them attentively with the microscope, were only a variety of the common or clear-winged species, else I should not have failed to have regarded them more particularly. All parts of this field of four acres were found to be infested more or less with the wheat-fly, but they occurred most abundantly along one of its sides, in the field adjoining which, wheat had been grown the preceding year, which had been considerably injured by this insect. Such a host of destroyers as were here found, and the profusion of eggs that had been already deposited, strongly indicated that it must have commenced appearing in its winged state many days previous to this time. The wheat-fly may be met with daily, from the fere part of June, until so late at least as the middle of August. Although it congregates in swarms about fields of wheat at the time they are in blossom, it also occurs in a great variety of other situations. It often enters houses, upon the windows of which it may be observed dancing along the panes, sometimes in numbers. It may also be taken among the grass of pastures, and of alluvial meadows that have never been turned up 16 by the plow. It is sometimes found in shady places, particularly along the margin of streams, associated with other minute species of Tipu- lidce in those dances in which swarms of these insects so often engage. One specimen was met with on weeds, in the margin of an entensive and dense forest, through which it must have made its way, or over an adjoining lake a half mile broad, on the opposite side of which was the nearest cultivated ground. The fly during the sunshine of day moves about but little, remaining mestly at rest or lurking about in the shade furnished towards the roots of the growing grain. In the twilight of evening it becomes active and continues so perhaps during the entire night; for before the morning sunrise it may be seen abundantly upon the wing, though less agile than in the evening, as though it had now become somewhat wearied or was rendered sluggish by the coolness and dampness of the night air. Upon cloudy days, also, it resorts but little to its usual retreats. In short, it appears to be only the direct rays of the sun which it avoids, for if a tree be standing in an infected wheatfield, the fly may be met with in its shade, on the wing and depositing its eggs at mid- day. Hence those parts of a field shaded by trees or an adjoining wood, have been repeatedly observed to be severely devastated or even entirely destroyed, when the other parts of the same field have been but moderately injured. But it is during the evenings which succeed hot days of sunshine that the fly appears to be most busy and full of life. If a field infested with them be visited with a lantern at this time, such hosts as were little imagined to exist, will be found busily hovering about the grain, the most of them wath wings and legs extended, dancing, as it were, slowly up and down along the ears, intently engaged in selecting the most suitable spot where to deposit their eggs. This being found, the insect alights, and standing upon the outer glume or chaff of the ker- nel, curves its abdomen so as to bring the tip in contact at right angles with the surface of the glume. It now toils industriously to insinuate its ovipositor through the scale, which is not accomplished till after a considerable exertion. Sometimes even, the scales having probably acquired too much maturity and hardness to be pierced by the tiny stinger which the fly protrudes, it is foiled in its efforts, and, as if vexed at its ill success, spitefully jerks its wings apart and darts away. This occurrence, however, is rare. And having penetrated with its 17 ovipositor into contact with the germ of the future grain, through this tube one egg after another is passed in at short intervals until several are deposited. The usual number of eggs thus deposited, appeared to be from six to ten; and as thrice or four times as many larvae can sometimes be met with on a single germ, it is probable that three or four insects sometimes successively puncture the same floret. Very frequently two, four or six flies may be seen at the same time on diffe- rent florets of the same ear, depositing their eggs; and Mr. Shirreff says, " Upon one occasion I numbered thirty-five flies on a single ear, and, after carrying it a distance of a quarter of a mile, six of them still continued to deposit eggs." This work being done, another labo- rious task for the tiny creature remains, that of withdrawing the oviposi- tor ; and to accomplish this, the energies of the insect are sometimes inadequate, and it remains, Prometheus-like, chained to an immoveable mountain, until it expires. This curious fact, first observed by Mr. Kirby, I have seen fully verified, meeting in several instances with the dead insect still remaining thus suspended. Although the flowers of the wheat are the favorite resort of this insect for depositing its eggs, yet it is not limited solely to this plant. It is currently reported to have been occasionally met with in rye and oats in this country. Mr. Shirreff and Mr. Gorrie both found the wheat-worm in ears of the quack or couch grass {Triticum re- pens Linn. ; Agropyron repens, Pal. de Beauvois); and the latter gentleman hereupon rather naively remarks, " The fly has not known that modern botanists no longer ranged the couch grass among the wheat tribe : but, like myself, it is most attached to the Linnaean names and systems." Mr. Markwick also found the same worms in the wild bearded oats {Avenafestuca, Linn.) The eggs are of an oblong, cylindrical form, with rounded ends, They are pellucid and nearly colorless at first, but acquire a yellow- ish tinge ere they are hatched, which is in rather over a week after they are deposited. The larva has two distinct stages in its existence : an active or 'growing state, which is passed through in about a month ; and a dormant state, which then supervenes, and continues through the winter. This latter has been generally but incorrectly regarded as its pupa state by writers. When it comes from the egg, the larva is a minute oblong soft 2 18 worm, without feet or hairs, and transparent or of a whitish tinge at first, but soon changing to a bright amber or orange yellow. It moves but slowly, and with difficulty, by a wriggling motion of its body. It remains within the particular floret in which it is hatched, until it attains its full growth. Mr. Kirby says it feeds upon the pol- len of the anthers; and perhaps it does so at first, but certainly whilst they are quite small, all the worms within the floret clus- ter upon the sides of the germ, and generally towards its base (Plate 5, fig. a.) I apprehend they chiefly subsist and attain their growth there, upon the fluids destined for the nourishment of the germ, and which, for want of these fluids, becomes shrivelled to a greater or less degree, and does not attain that plump form on which the value of this grain so much depends. The amount of injury re- ceived by the individual kernel of grain varies according to the num- ber of worms that have been nourished in the chaff in contact with it. If mature worms grow from all the eggs deposited by the fly at a single puncture, the kernel is doubtless rendered worthless ; but a single worm, as is occasionly found, would scarcely produce a per- ceptible effect. Having attained its growth, and in its dormant state, it does not differ sensibly, as I have been able to discover, from its previous ap- pearance ; and the only reason for marking this as a distinct stage, is, that the insect now remains for a long period (probably two-thirds of its entire term of existence) without increasing in size or under- going any other perceptible change. The texture of its body seems to have acquired rather more firmness than it possessed while it was growing, and its motions are more sluggish. It is less than the tenth of an inch long : a measurement of several specimens gives 0.07 as their average length. It is of a rich orange color, and of an oblong-oval form (Plate 5, fig. b), being broadest in the middle and rounded at each end : it is slightly depressed, the under side being considerably flattened ; thus in form somewhat resembling the leech when contracted. Its joints are indicated by slight transverse im- pressed lines, by which it is divided into twelve segments of about equal length. Sometimes a brownish cloud is perceptible near the middle of the body on its underside, which is probably caused by alimentary matter. If these worms are placed for some days on a plate in a dry room, the outer skin of the body becomes so dry and 19 indurated that the worm is incapable of making the slightest motion j but on covering them with a wetted cloth, the surface again in a short time becomes pliant and yielding; and if pressed with a needle, the animal writhes, and sometimes turns itself over to escape from the annoyance. I doubt whether it ever moults, or casts off its skin between its egg and its pupa state ; but my observations have not been sufficiently exact and prolonged to speak positively upon this point. This is the form in which the insect passes the autumn and winter. The accounts of writers disagree as to where the worm remains during this period; in fact few of them speak distinctly upon this particular point. Mr. Kirby, however, describes the worm as still continuing in the heads of the wheat ; but as a considerable portion of them are missing, he thinks these have been destroyed by para- sitic enemies. He says, " I have seen more than once, seven or eight florets in an ear inhabited by the [active] larvae, and as many as thirty in a single floret, seldom less than eight or nine, and yet I have scarcely found more than one pupa [dormant larva] in an ear, and had to examine several to meet with that." Mr. Gorrie, on the other hand, asserts that the maggots quit the ears of the wheat by the first of August, and enter into the ground, where they remain through the winter. Mr. Shirreff, also, from finding the fly much more abundant in fields where wheat had been grown the preceding year than it was in other fields, entertains the same opinion. Now the truth is, Mr. Kirby and Mr. Gorrie are both right. A portion of the larvae leave the grain before it is harvested, and descend to the ground, where I have found them, under mouldy fragments of straw on the surface, or buried a half inch or less within the soil. I thus found them, common in the field already spoken of as examined on the 16th of June, a few days after the grain was harvested ; and also early in March, in a field in which wheat was grown the pre- ceding year, that had been somewhat injured by the fly. Another portion of these larvae remain in the heads of the wheat, and are carried into the barn, where they may readily be observed upon the threshing-floor, and found in quantities among the screenings of the fanning-mill, a considerable portion of which sometimes consists of these worms. Thence our farmers kindly empty them out at the door of the barn, where most of them doubtless find among the litter 20 of the yard a bed equally as comfortable and secure as that in which their brethren in the field are at this time reposing. Whence does this singular diversity in the habits of these larvae arise 1 All the worms are undoubtedly fully matured before the grain becomes ripe and dry and hard. Why then do one part of them leave the wheat heads and enter the ground ere the harvest— and another portion of them remain within the ears to be carried into the barn with the grain when it is housed ? Two well attested ob- servations, I think, shed important light upon this interesting point. And if the inference which I deduce from them be correct, we have arrived at another very curious trait in the economy of this insect. Dr. Harris informs us, that " after a shower of rain, they [the larvae] have been seen in such countless numbers on the beards of the wheat, as to give a yellow color to the whole field ; " and he refers to the New- England Farmer, vol. xii. p..60, in confirmation of this statement, a volume which I have not at hand. For an analogous but still more instructive fact, I am indebted to Gen. M'Naughton, a practical far- mer of this town, the accuracy of whose statements no one acquainted with him will doubt. In 1832, his wheat, in which the fly had made sad havoc, was cradled and lying in the swath, when a moderate rain came on, followed by a damp cloudy afternoon. At this time, with his hired help, herepaired to the harvest-field to bind up the grain. They here found not only the heads, but also the straw in its entire length sprinkled over with these worms. On my observing to him, that I could scarcely believe it possible for a footless worm to crawl along the straw when it was lying horizontally, he stated that he was par- ticularly positive with regard to that fact ; for he distinctly recollect- ed that it was impossible for him to draw the band around a bundle and tie it [in which process the heads of the grain are not touched,] without having at least a half dozen of these worms adhering to his hands. From these facts, I infer that the worm does not crawl out of the chaff and " drop " itself to the ground, as has been stated by some writers ; but that having attained its growth, it lies dormant within the chaff, awaiting a favorable state of the weather in which to make its descent, to wit, a rain which is not immediately followed by a clear sky and warm sun that would soon dry the straw. Hence it is doubtless almost invariably by night that this journey of the worm 21 is performed, and that it has therefore never been seen. The straw itself being wet, and the body of the worm rendered supple by the moisture surrounding it, it leaves its abode in the head of the wheat, 'and adhering to the wet straw by the glutinousness of the surface of its body, 'gradually works its way downwards by the wriggling motion to which it so often resorts when disturbed, until it reaches the ground. That there is such a glutinous secretion upon the sur- face of the worm as would enable it to adhere to the wet straw in the manner supposed, I might adduce a number of facts to prove. I was desirous of taking a drawing of the larvae which I found among wheat-stubble last March ; but particles of earth adhered to them so firmly, that I could not separate them with the point of a needle without also mutilating the worms. A few weeks since, on visiting a neighbor's threshing-floor, I gathered a number of larvae by mois- tening the end of my finger and touching it to the worm, which, thus adhering, was scraped off upon the edge of a tin box. The box is now before me, with each of the worms alive, but firmly glued to its sides, and many of them to each other ; and on forcibly removing some of them, the outer dried and hardened case of the worm is fractured in the operation. It would thus appear that those worms which are matured, leave the grain at the close of a shower, and crawl down the wet straw to the earth. It may be also, that a heavy night-dew sometimes fur- nishes a sufficient degree of moisture to enable them to do this. But on the other hand, those worms which are later in arriving at maturity, in awaiting suitable weather for making the same descent are, ere such weather arrives, carried with the grain into the barn. As illustrating the strong tenacity of life possessed by these larvae, I may in this connexion state, that the few specimens gathered in March as already stated, were placed with a little earth in a vial, and a piece of gauze tied over its mouth, for the purpose of ascertaining the transformations of the insect, if any, from its then condition lo that of a winged fly. Other avocations diverted my attention, and this vial was forgotten for a fortnight; by which time the earth within had become so completely dried, that not doubting but the worms had all perished, no farther attention was paid to it, and it remained in a dry room over three months, until the middle of June, when, on ex- amining it, half the specimens put into the vial were found to have 22 completed their transformations ; a corresponding number of dead wheat-flies being found attached to a straw in the upper part of the vial. Prof. Henslow thinks that it is only those larvae that are punctured by ichneumons, that leave the wheat-ears and enter the. ground; but the facts now stated show that this opinion is erro- neous. On removing the earth from the vial above alluded to, the cases of the pupa from which the flies had proceeded, were found very per- fect. These conclusively showed that ihe real pupa is not formed until in the spring, and that it is then altogether different in form from what has been described by writers as its pupa. It corresponds identically in its appearance (perhaps with the exception of color) with that of the Cecidomyia Salicis, as exhibited in the first volume of the American Quarterly Journal of Agriculture and Science. Plate 2, fig. 1. It also closely resembles the figure of the pupa .of Cecidomyia Pini ? as given from De Geer in Westwood's Introduc- tion to the Modern Classification of Insects, vol. ii. p. 518, fig. 125, No. 7.* Its length is slightly less than that of the dormant larva. The antennae, legs and wings, are each enclosed in separate sheaths, which lie externally to the integument in which the body is envelop- ed. The three pairs of legs all lie parallel and in contact with each other upon the breast, reaching far down past the tips of the wings ; the inner pair being shortest, and the outer pair longest. Judging from the analogy afforded by the Cecidomyia Salicis, I presume the wheat-fly only remains in its pupa state three or four weeks in the latter part of May and the fore part of June. its natural enemies. One of the most effective natural destroyers of the wheat-fly, is undoubtedly our common yellow-bird (Fringilla tristis, Lin.) Fields much infested by the insect, have been for many years recognized even by passers on the highway contiguous to them, by the rough and ragged aspect of the heads of the grain (Plate, fig. c). I am not aware that the cause of this peculiar appearance has ever been sta- ted in any of the communications that have appeared in our agricultu- * I cannot but regard the figure here referred to as inaccurate, in representing the wings as enclosed in one common case, over which the legs are laid. The tips of the wings should, probably be rounded, instead of being brought to a point. 23 ral papers. It results from the operations of this bird. Alighting, it adroitly grasps the wheat stalk just below the ear, and clinging fear- lessly to it, even when swayed to and fro by the wind, it with its bill parts down the chaff from the grain, and one after another of the worms to which it thus gains .access are rapidly picked off and devoured. Thus several heads are generally freed from the worms, ere its repast is completed. That it is the worms and not the grain that it is in pur- suit of, is readily ascertained by an inspection of the heads after the bird has left them : many of the kernels, not being sufficiently loosened to drop to the ground by the operation, will be found remaining, the maggots that were upon them only having been removed; whilst those kernels of the head which are not infested by the worm, are passed over untouched. It is curious that this little creature, by a tap with its horny bill, or some other process, is enabled to distinguish those scales of chaff which conceal so minute a worm, from those which do not; a knowledge which we only arrive at when we have parted down the chaff. A flock, numbering about fifty, embracing both male and female birds, appeared to make the field which I examined on the 16th of June their constant resort, for a period of three weeks or more, where they could be seen busily occupied almost constantly every- day. The number of worms consumed by them during this time must have been immense ; and I cannot but believe that this lovely bird will henceforward be esteemed for its utility, as much as it has hereto- fore been for its beauty. I have as yet found but one insect parasite, which I am well assured subsists upon and destroys the worm of the wheat-fly. It is a hyme- nopter of the family Chalcididce ; but my acquaintance with the de- tails of its history is as yet too limited to attempt an account of it. I shall be much disappointed if I do not meet with still other species which prey upon the wheat-fly; and as all these parasites upon the Cecidomyia? are more or less closely related to each other, they can probably be most advantageously presented in a separate article devo- ted exclusively to that subject. Four or more species are known abroad, which destroy the wheat- worm. One of these, it is stated in the first volume of the Edinburgh Quarterly Journal of Agriculture, deposits an egg beside an egg of the wheat-fly, the worm from which devours the wheat-worm soon after it hatches, and thus effectually saves the wheat. The observations of 24 Mr. Shirreff upon another of these cannot but interest the reader. He says, " Upon presenting four larvae (of the wheat-fly) to an ichneumon, it soon stung, or, according to Mr. Kirby, deposited an egg in each of their bodies, and stung one of them a second time. The maggot writhed in seeming agony, and straggled upon my thumb-nail, where it was again stung three times by the same fly ; and in a second strug- gle, both fell to the ground." ARTIFICIAL MEANS FOR ARRESTING ITS RAVAGES. These may be divided into two classes, as they refer to the protec- tion of the grain from the fly when in its winged form and depositing its eggs ; or as they directed to the destruction of the fly itself, in the previous stages of its existence. Several measures have been proposed, and some of them with much confidence and plausibility of reasoning, for protecting the wheat crop from this insect during the period of its blossoming. The more pro- minent of these I will advert to. The smoke of a number of smouldering fires, or of brimstone matches, in different parts, and particularly upon the windward side of an infested field, has been recommended. The known efficacy of smoke in repelling the musketoe renders it probable that this remedy would be of signal utility, were it not for the discouraging amount of labor that is required to make so thorough and protracted a use of it as would be necessary. It has been suggested that the anal follicles of the skunk {Mephitis americana, Desm.) might • be extracted, and that yarn impregnated with the fluid contained in them, and suspended through wheat-fields, would, by its intolerable odor, banish the wheat-fly. I imagine that in carrying this suggestion into practice, the operator would be the great- est sufferer—" unless my nose deceives me." Sowing the field with lime at the time the wheat is in blossom, has been repeatedly, and by some with much confidence, urged. This re- medy has been much resorted to, and very conflicting statements with regard to its efficacy have been laid before the public. A simple ex- periment, directly to the point, is of more value than a thousand cases that tend to support any particular opinion ; and such an experiment I am prepared to narrate. Jarvis Martin, Esq., the owner of the infes- ted field repeatedly alluded to, at my suggestion, repaired to it one • 25 t evening, and sprinkled several of the heads with tolerably fresh air- slaked lime, until they were white with the powder adhering to them ; thus applying it far more profusely and effectually than can be accom- plished by