AMERICAN JOURNAL 



or 



AGRICULTURE AND SCIENCE. 



No. IX. JANUARY, 1847. 



INSECTS INJURIOUS TO VEGETATION.— No. V. 



BY ASA FITCH, M. D. 



THE HESSIAN FLY.— ( Continued.) 

 Its Characters, Transformations, and Habits. 



As a general rule, the Hessian fly passes regularly through two 

 generations annually. The first of these occupies the autumn, 

 winter, and fore part of the spring, and is reared at the roots of 

 the young grain, slightly below the surface of the ground. The 

 second occupies the remainder of the spring and the summer, and 

 is chiefly nurtured at the first and second joints of the straw. The 

 time when its several transformations occur, is not perfectly uni- 

 form, being varied by the climate, the state of the weather, and 

 perhaps other contingencies; and it is not improbable that indi- 

 vidual specimens, placed in circumstances unfavorable to their 

 development, have their growth retarded so much as to require 

 even a w^hole year to complete their metamorphoses. 



Pirst Generation, 



The Egg. When and where deposited. — The eggs of the first 

 generation are deposited chiefly in the fore part of September. 

 Dr. Chapman says the deposit is made from the latter end of Au- 

 gust till the 20th of September, and most other accounts coincide 

 with this, though some extend the time into October. On the 8th 

 of October the fly w^as seen ovipositing in Eastern Pennsylvania, 

 in 1819, and it had wholly disappeared on the 11th. {Jim. Far- 

 mer, ii., 180.) The deposit is doubtless made later at the south, 



No. IX. 1 



