274 [Senate 



completed their transformations ; a corresponding number of dead 

 wheat-flies being found attached to a straw in the upper part of the 

 vial. Prof. Henslow 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 erro- 

 neous. 



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

 the pupcB from which the flies had proceeded, were found very per- 

 fect. 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 Salicisy as exhibited in the first volume 

 of the American Quarterly Journal of Agriculture and Science. 

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

 Cecidomyia Pini ? as given from De Geer in Westwood^s Introduc- 

 tion to the Modern Classification of Insects, vol. ii. p. 518, fig. 125j. 

 No. 7.* Its length is slightly less than that of the dormant larva. 

 The antennee, legs and wings, are each enclosed in separate sheaths,. 

 which lie externally to the integument in which the body is envelop- 

 ed. The three pairs of legs all lie 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 fare part of June. 



ITS NATURAL ENEMIES, 



One of the most effective natural destroyers of the wheat-fly, is 

 undoubtedly our common yellow-bird [Fringilla tristis, Lin.) Fields 

 much infested by the insect, have been for many years recognized 

 even by passers on the highway contiguous to them, by the rough 

 and ragged aspect of the heads .of the grain (Plate, fig. c). I am 

 not aware that the cause of this peculiar appearance has ever been sta- 

 ted in any of the communications that have appeared in our agricultu- 



* I cannot but regard the figure here referred to as inaccurate, in repi-esenting the 

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

 wings should probably be rounded^ instead of being brought to a points 



