414 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. L18B5. 



This species would seem to be the most abuudaut of auy of the i)ar- 

 asites of the Hessian Fly, judging from the records of previous authors. 

 Packard, in his bulletin on the latter insect,* has collected statements 

 concerning the numbers in which tliese parasites occur. He quotes 

 Herrick to the effect that i^robably nine-tenths of every generation of 

 the Hessian Fly is destroyed by parasites, this species constituting the 

 larger proportion. He also quotes a Michigan correspondent, who 

 stated tliat in 1877 the Hessian Fly in Kalamazoo County was nearly 

 exterminated by the " Semiotellus," nearly all the " flaxseeds "' being 

 destroyed by it. 



The relative abundance of this and the other species of the same 

 genus is, however, in all probability, a question of latitude or location, 

 for, in the breeding from infested wheat received from Missouri, the 

 species descriped as suhapterus in tliis paper has been much the most 

 common. 



The eggs of this j)arasite are without much doubt deposited in the 

 half-grown larvte of the Hessian Fly early in the spring, and in the 

 jnore southern portions of the wheat belt there are in all probability 

 two generations, the first issuing from the puparium in April and May, 

 and the second issuing all through the summer and fall. Many, judging 

 from my experience in-doors, hibernate in the pupa state within the 

 Cecidomyid i)uparium, and cut their way out the following spring. In 

 the North, however, there seems to be but one annual generation. 



The so-called puparium is at first really nothing but a rigid, quies- 

 cent larva, corresponding to what I have called the coarctate larva in 

 the Meloidse, and it will help to prevent confusion if we do so desig- 

 nate it in the Hessian Fly, up to the period when the real pupa is formed 

 within it, for it must not be forgotten that another soft and final larva 

 stage is assumed within this coarctate larva shell, and lasts much longer 

 than the pupa state proper. I would restrict the term puparium in this 

 case to the period during which the pnpa proper dwells within it. 



Whether or not there exist wingless individuals of this species be- 

 comes extremely doubtful. So far as my own breeding is concerned, 

 none have been obtained. Harris makes no reference to them, nor does 

 Packard in his description of the species. Say makes no reference to 

 them in his description proper, but in the notet which Mr. Howard 

 has called attention to as having been omitted from the Le Conte edi- 

 tion,! he remarks that the parasite " throws oft' its wings as a useless 

 incumbrance," &c. So far as I am aware this habit does not occur in 

 any of the species of the family and there has certainly been no tendency 

 in that direction among the specimens that have come under my ob- 

 servation. 



* Bull. 4, U. S. Entomological Commission, Washington, 1880. Reprinted, with 

 additions, in the third report U. S. E. C, Washington, 1883. 



t Jonrnnl of the Academy of Natuial Sciences of Philadelj^hia, July, 1817, vol. i, 

 p. g;5. 



X See Psyche, vol. iv, p. 200. August, September, 1884. 



