ARTICLE IIL 



On the Cecidomyia Destructor, or Hessian Fly. By Miss M. H. Morris. Read 



Oct. 2, 1840. 



The enormous injury to which the wheat crops in the United States have 

 been, for many years, subjected by the Cecidomyia Destructor, or Hessian Fly, 

 induced me to study, minutely, the habits of the insect, with a view to discover 

 some remedy for the evil. Having ascertained that the perfect fly appears in 

 June, and lives but a few days, and that the larva is only to be found in the 

 young wheat, in the succeeding fall, or spring, I was led to infer that the grain 

 itself was the nidus selected, not the culm, as Mr. Say had supposed. 



The fact of the egg being laid in the grain does not, however, rest upon in- 

 ference ; I have actually detected the larva in the grain, when peculiar circum- 

 stances had prevented it from leaving its birth-place, in order to ascend the 

 stalk, as it is prone to do. 



While I admit the correctness of Mr. Say's description of the Cecidomyia, 

 given in the first volume of the Journal of Natural Sciences, I must beg leave 

 to differ from him respecting the history of the insect. He alleges " the egg 

 to be deposited in the stalk of the wheat, between the vagina and the culm, 

 near the root," and that, "in this situation, with the body inverted, the head 

 being invariably down, the infant larva passes the winter;" here he leaves it, 

 and proceeds to describe its appearance in the flax-seed state, evidently sup- 

 posing that it had not moved from its position from the time of its exclusion 

 from the egg until its change to the pupa. He then states that " the perfect 

 fly appears early in June, lives but a short time, deposites its eggs, and dies." 



VIII. — N 



