1836] 



FARMERS' REGISTER. 



113 



two. In making selections for setting, none but the 

 finest kinds lor size and flavor should bo chosen, as 

 a bush the fruit of" which is small and worthless 

 will occupy as much room as one which unites ali 

 the yood qualitcs desired. 



G. 



From the Genesee Farmer. 

 THE HESSIAN FLY. 



One of our new subscribers in Ohio, has ex- 

 pressed a wish to see a dissertation on the Hes- 

 sian fly; and as it may be acceptable to other of 

 our readers, we shall attempt to furnish briefly, 

 the most im[)ortant of the information which we 

 possess respecting it. 



This insect belongs to the order Diptera, which 

 includes all those insects having only two wmgs, 

 and to the genus Tipuld. The number of species 

 belonging to this genus are numerous, amountmg 

 to more than one hundred and thirty of those 

 hitherto known and described, and as many of 

 these resemble each other, care is necessary, in 

 observations on the Hessian fly, that no mistakes 

 are made in identifying the species. 



The following description of the Hessian fly, 

 (Tipiila vaginalis tritici of Mitchill,) is given by 

 Dr. Akerly, in the American Magazine and Crit- 

 ical Review, of August, 1817. "It is a very small 

 black insect, not so large as the moscheto of this 

 place,* with two fine transparent wings, from the 

 roots of which, three ribs diverge, as through the 

 leaf of a [)lant. The body, when examined by a 

 microscope, is found to be divided into four seg- 

 ments, with a icw hairs observable on each. 'J'he 

 legs are of a yellowish cast, and transparent; the 

 head inflected, with a sliort proboscis " 



This, in common with nearly all other insects, 

 passes ihrnuo-h four distinct staires of existence: 

 1, the egg; 2, the larva, or magijot; 3, the pupa, 

 or dormant state; and 4, the perfect winged insect. 

 In this part of the country, it passes through 

 two generations in one season, and attacks the 

 wheat both in the spring and in the autunm. The 

 fly, or perfect insect, deposites its eggs in the au- 

 tumn, soon after the young plants appear above 

 ground, between the lowest part of the leaf and 

 tnat part which forms the main stem or straw, 

 and as near the root as possible. "It resembles, 

 at first, a very small white nit, and as it grovvs 

 larger become a sluggish and almost inanimate 

 maggot, of a white color. In this state, the pro- 

 per and most natural food is the sap or juice of 

 that kind of green wheat which has the most del- 

 icate straw."! It remains in this situation through 

 the whole winter, apparently in the chrysalis state, 

 without suffering any injury ii-om the frost or 

 snow; and in the spring, as soon as the weather 

 becomes warm enough, and generally about the 

 lime vegetation has fairly commenced, it is trans- 

 formed into the fly. In this state it performs the 

 functions necessary for a continuation of its species. 

 It lays its eggs between the straw or stem and the 

 sheath whicli encloses it, as before described, and 

 dies; and a new generation succeeds. 



These eggs are soon hatched by the warmth of 

 the season; and the young insects may be thsco- 



* Its body is about one-ninth of an inch in length, 

 t Havens on the Hessian fly, in Agric. Trans. New 

 York, vol. 1, p. 77. 

 Vcl. IV— 15 



vered in the form of email white maggots, with- 

 in the sheath of the straw, and just above the 

 lower joints. They here continue to feed upon the 

 sap and tender fibres of the plant, by which it either 

 withers and dies, or is stunted in its" growth, so that 

 the grain docs not arrive at maturit}'. They are 

 changed into the pupa slate before harvest, and at 

 this season, while the wheat is yet green, their 

 presence may be readily detected by walking 

 through the field and pressing the heads with the 

 fingers; those which feel soft, and unfilled with 

 grains, are those which have been injured by the 

 insect; and if tlie stalk be examined, they will be 

 Ibimd near the lower joints, somewhat resembling 

 a flax seed, but smaller and slenderer, and of a 

 diirk brown color. They continue in this state 

 till after harvest, and may be found upon the stub- 

 ble in the field. Early in autunm they pass into 

 their winged state, and lay their eggs in the 

 young plants of wheat as before described. 



When the fly is about to' issue from the pupa 

 into the state of perfect insect, it disengages it- 

 self by boring a small round hole through the 

 brown case m which it is enclosed, and through 

 the sheath of wheat just opposite to the place 

 where it lodged, and this hole may be easily dis- 

 covered as long as the stubble remains entire. 



With regard, to the time of undergoing its final 

 transformation the first time in the season, Judge 

 Havens observes, "the size of the majigot when 

 full grown, and >he time necessary to complete its 

 growth, depend in a great degree upon the quan- 

 tity of nourishment it may obtain from the grain, 

 and the number of maggots that may happen to 

 be on one straw. This, according to the best of 

 my observations, is somewhere betv\een four and 

 six weeks, which will bring the time, in which its 

 growth will generally be completed, to the first 

 part of June. But here the several causes of va- 

 riation in the time of its being laid in the wheat, 

 and of its completing its growth, both conspire to 

 render this time so various, that some will be 

 full grown, and others transformed into a chrysalis 

 [pupa,] Vk'hile others are small; and this circum- 

 stance has no doubt led many skilful observers to 

 suppose, that there are two complete generations 

 of the insect before harvest." The second time 

 that the fly issues fi'om the pupa, depends also in 

 a great degree, on circumstances. "It generally," 

 says Havens, "begins about the 20lh or 25lh of 

 August, and continues in a greater or less degree 

 through the whole month of September; but by 

 far the greater part of the species are without 

 doubt transformed into a fly, in the first part of this 

 latter month." 



B)^ understanding the history of this insect, we 

 are enabled to appljMhe means for its destruction, 

 or for escaping its rav-ages. As it remains upon 

 the stubble in the pupa state after harvest, the first 

 means to be used, is, to destroy the stubnle soon 

 after cutting the wheat. This is to be done either 

 by ploughing or by burning. If by the former, the 

 pupa is buried in "the earth, and is thus prevented 

 from changing to the fl\'; or if it changes, it cannot 

 escape. Unless therefore, the stubble be complete- 

 ly buried, the experiment will not succeed, conse- 

 quently the deeper the ploughino; the better. If by 

 the latter, thestubble must be entirely burnt in order 

 that the destruction may be complete, for, as the 

 insect lies near the root, it will escape, unless the 

 fire be well applied. 



