174 ORDER DIPTERA. 



As regards it< origin, it appears from the numerous accounts published at different times 

 during the la-t half century, that the hessian-fly is nut indigenous to this country, but wae 

 unpolled iu straw from Europe by the lie>sians in the emploj of the English government 

 about the year 1776. Tlie laets which go to sustain this \ iew of the question are, thai aa 



• el had appeared in Germany, and committed ravages upon tlie wheat crap pri< r to it > 

 appearance in this country : and that the habits and characters of this german insect agree 

 with those of the one named in tins article. It i- farther shown by the history of its pro- 

 gress in this country, that it was first observed upon the western extremity of Long Island, 

 and on Btaten Island, in the immediate neighborhood of the grounds occupied by this 

 branch of th< K glish army ; and that from this centre it spread in all directions, travel- 

 ling slowly over the cultivated parts of the country, and destroying the wheat crop in its 

 course. Its march, and the consequent destruction of the wheal crop, was marked by an 

 increase in its numbers, and in the amount of its injury for an uncertain number of year-, 

 when it gradually disappeared from the country it had occupied and wasted. After long 

 intervals of freedom from the ravages of this fly, it gradually returns and renews its at- 

 tacks upon the wheat crop, running about the same course in its second as in its first 

 visitation. It has ven recently passed over parts of Maryland and Virginia. I observed it 

 in the former State in 1849. I think we may infer from it- history and progress, that in all 

 parts of the United States where wheat is cultivated as a staple product, it will continue 

 it- injurious career hereafter as in times pa>t. 



The species of fly which has received the name Cecidcmyia destructor from the di>tin- 

 guished entomologist Say, possesses the following specific characters : Female, head black, 

 flattened, globular ; antennae about half the length of the body, and composed of sixteen 

 oval joints furnished with a whorl of minute hairs, the two basal joints close and globular, 

 terminal joint the longest ; palpi three-jointed, hairy ; thorax black, oval, broadest behind 

 the wimx-sockets ; scutel black ; poisers only dusky ; abdomen black above ; sutures 

 tawny fulvous, elongate ovate, scarcely equalling the thorax in width; ovipositor rose-red : 

 wina< dusky, fulvous at their base ; legs equal, pallid brown; tarsi black, equalling the 

 legs in length. Male : antennas three-fourths the length of the body ; joints globular, 

 and furnished with hairs as those of the female ; filaments separating the joints, about as 

 long as the joints : abdomen brownish black, cylindric, seven-jofn'ted and slightly tapering, 

 the extremity armed with two robust processes having incurved hooks at their tips. 



It appears from Dr. Fitch"s statement, that in the spring the perfect insect remains but 

 about a week, during which time it deposits its eggs for the summer brood. The first brood 

 appears about the first of May in Northern New-York, and of course is hatched from eggs 

 that were laid the preceding autumn ; the insect having subsisted upon the juices of the 

 herbage, or lain in a dormant state from that time. Early in May, then, the fly deposits 

 its eggs, in the same field, upon the more succulent leaves, near their insertion with the 

 stem of the plant, which it may readily reach after being hatched. After a time the worm 



