32 



This history of the Hessian fly agrees closely with that of the 

 wheat bulb worm, which insect is now also known to be unques- 

 tionably three-brooded. The period of the second brood coincides 

 almost exactly with that of the Hessian fly, the third brood agreeing 

 also, except that it is somewhat retarded in its later stages, hibernat- 

 ing only as a naked larva, and not reaching the imago stage until 

 May, — nearly a month later, on an average, than the corresponding 

 stage of the fly. The first brood of the Meromyza is correspond- 

 ingly later than the other in its origin, but passes through its 

 transformation more rapidly, development from the egg to the 

 imago occurring, so far as our observations show, within the'limits 

 «of }a single month. 



