590 
DIPTERA. 
oval form, tapering at each end. The pupae found in the 
ears were very few in number, scaicely one to fifty of the 
maggots. Hence Mr. Kirby supposes that the latter are 
not ordinarily transformed to flies before the spring. To- 
wards the end of September he carefully took off the skin 
of one of them, and found that the insect within still retained 
the maggot form, and conjectures that the pupa is not usu- 
ally complete until the following spring. 
It is evident, from these observations, that the English 
naturalists above named regarded the insect as having en- 
tered upon the pupa state when it ceased feeding and became 
quiescent, at which time Mr. Kirby found it generally to 
adhere somewhat to the grain. In applying to it, in this 
condition, the name of chrysalis or pupa, and describing it as 
such before it exhibited any trace of “ the lineaments of the 
future fly,” and while “ still in the form of the larva,” they 
followed the common usage of naturalists, as stated in my 
account of the Hessian fly. They cannot, therefore, be 
said to have mistaken the larva for the matured pupa ; the 
remarks of Mr. Kirby prove that he was well aware of the 
difference between them. Mr. Kirby, however, was mis- 
taken in his conjecture that “ the insect enclosed itself in a 
thin membrane to protect itself from the cold of the win- 
ter ” ; the membrane referred to being merely the outer skin 
of the larva, loosened previously to being cast off entirely, — 
a process which he did not observe. 
According to Mr. Gorrie, the maggots quit the ears of the 
wheat by the first of August, descend to the ground, and 
go into it to the depth of half an inch. That they remain 
here unchanged through the winter, and finish their trans- 
formations, and come out of the ground in the winged form, 
in the spring, when the wheat is about to blossom, is ren- 
dered probable from the great number of the flies found by 
Mr. Shirreff, in the month of June, in all the fields where 
wheat had been raised the year before. The increase of 
these flies is somewhat checked by the attacks of three 
