174 ORDER DIPTERA. 



As regards its origin, it appears from the numerous accounts published at dilTercnt times 

 daring the last half century, that the hessian-fly is not indigenous to this country, but was 

 imported in straw from Europe by the Hessians in the employ of the English government 

 about the year 1776. The facts which go to sustain this view of the liuestiou ai*, that an 

 insect had appeared in Germany, and committed ravages upon the wheat ciop prior to its 

 appearance in this country ; and that the liabits and characters of this german insect agree 

 with those of the one named in this article. It is 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 Staten Island, in the immediate neighborhood of the grounds occupied by this 

 branch of the English 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 wheat crop, was marked by an 

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

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

 intervals of freedom from th« ravages of tliis 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 very recently passed over parts of Maryland and Virginia. I observed it 

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

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

 its injurious career hereafter as in times past. 



The species of fly which has received the name Cecidomyia destructor from the distin- 

 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 wing-sockets ; scutel black ; poisers only dusky ; abdomen black above ; sutures 

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

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

 1^8 in length. Male : antennae 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-jointed 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 



