194 



FIG. 237. The Hessian fly and its transformations. 



A. healthy stalk of wheat on the left, the one on the right dwarfed and the lower 

 leaves beginning to wither and turn yellow; the stein swollen at three places, 

 near the ground where the flaxseed (h) are situated, between the stem and 

 sheathing-base of the leaf, a, egg of the Hessian fly (greatly enlarged, as are 

 all the figures except e and h); b, the larva, enlarged, the line by the side, in 

 this and other figures, showing the natural length; c. the flaxseed. pnparium, 

 or pupa-case; d, the pupa or chrysalis; e, the Hessian fly, natural size, laying 

 its eggs in the creases of the leaf; /, female Hessian fly, much enlarged: g, 

 male Hessian fly, much enlarged; h, flaxseed between the leaves and stalk; 

 i, Chalcid parasite of the Hessian fly, male, enlarged. Fig. 6 drawn by Mr. 

 Riley; Fig. d by Mr. Burgess; Figs, a, c, and i, by the author; h, g, f, drawn on 

 wood by L. Trouvelot. Wo face page 195.) 



