ORDER VII.—TWO-WINGED INSECTS, OR FLIES. 305 
occupied more than two hundred sheets of paper. At last 
Sir Joseph Banks, a distinguished naturalist in England, was 
applied to for information; but so little was known of ento- 
mology here that, although whole packages of descriptions 
were forwarded to him, he could not explain whether the 
injurious insect was a moth, a bug, or a fly. 
Soon afterward, however, the natural history of the Hes- 
sian-fly, and the measures necessary to prevent its ravages, 
became the subject of investigation of several scientific gen- 
tlemen, among whom were Dr. Isaac Chapman, in the 
“Memoirs of the Philadelphia Society for the promotion 
of Agriculture ;” Jonathan N. Havens, Esq., in the ‘‘ Trans- 
actions of the Society for promoting Agriculture in New 
York ;’’ Mr. Herrick, in the ‘“‘ American Journal of Sci- 
ence;” Iir. Edward Tilghman, of Maryland, in the “ Culti- 
vator;” and, above all, our distinguished naturalist, Thomas 
Say, in the “Journal of the Academy of Natural History 
of Philadelphia.” From the researches of these distin- 
guished men we derive the following information: 
The Hessian-fly is very small, and its body and wings are 
entirely black. The female deposits her eggs on the stalk 
or leaves of wheat, barley, rye, and Timothy grass, as soon 
as the plants are up in the spring or fall, the maggots from 
which enter the stalk and feed upon its substance and sap, 
thereby weakening the stem and causing it to break and 
fall before the grain is ripe. The eggs are very diminutive, 
of a reddish color, and are hatched by the caloric of the at- 
mosphere, according to the temperature, in one or two 
weeks. The maggots are also of a reddish color, and as 
soon as hatched fasten themselves on one of the joints and 
suck the sap of the stem, until after five or six weeks they 
attain their full size, and then change into light-brown 
pupz from which the perfect insect soon emerges. This 
process takes place at least twice, and sometimes thrice a 
year, upon the wheat and other grain that grows in spring, 
— 
