250 QUARTERLY JOURNAL. 



lion to that of a winged fly. Other avocations diverted my attention, 

 and this vial was forgotten for a fortnight ; by which time the earth 

 within had become so completely dried, that not doubting but the 

 worms had all perished, no farther attention was paid to it, and it 

 remained in a dry room over three months, until the middle of June, 

 when, on examining it, half the specimens put into the vial were 

 found to have completed their transformations ; a corresponding 

 number of dead wheat-flies being found attached to a straw in the 

 upper part of the vial. Prof. Henslovv thinks that it is only those 

 larvae that are punctured by ichneumons, that leave the wheat-ears 

 and enter the ground ; but the facts now stated, show that this 

 opinion is erroneous. 



On removing the earth from the vial above alluded to, the cases 

 of the pupcB from which the flies had proceeded, were found very 

 perfect. These conclusively showed that the real pupa is not formed 

 until in the spring, and that it is then altogether different in form 

 from what has been described by writers as its pupa.* It corresponds 

 identically in its appearance (perhaps with the exception of color) 

 with that of the Cecidomyia salicis, as exhibited in the first volume 

 of this Journal, Plate 2, fig. 1. It also closely resembles the figure 

 of the pupa of Cecidomyia pini ? as given from De Geer in West- 

 wood's Introduction to the Modern Classification of Insects, vol. ii. 

 p. 518. fig. 125. no. T.f Its length is slightly less than that of the 

 dormant larva. The antennae, legs and wings, are each enclosed in 

 separate sheaths, which lay externally to the integument in which 

 the body is enveloped. The three pairs of legs all lay parallel and 

 in contact with each other upon the breast, reaching far down past 

 the tips of the wings ; the inner pair being shortest, and the outer 

 pair longest. Judging from the analogy afforded by the Cecidomyia 

 salicis, I presume the wheat-fly only remains in its pupa state three 

 or four weeks in the latter part of May and the fore part of June. 



* Since making this discovery, I have strongly suspected that the pupa of the hessian 

 fly has never been as yet detected ; and that its "flaxseed state," which has all along 

 been regarded as its pupa, is only the same state which I have described as the dormant 

 larvffl of the wheat-fly. 



1 1 cannot but regard the figure here referred to as inaccurate, in representing the 

 wings as enclosed in one common case, over which the legs are laid. The tips of the 

 wings should probably be rounded, instead of being brought to a point. 



