except in cases where the youno- plant has become disintegrated and 

 separated at the point of attack in the fall or tlie phints have been 

 heaved out by the action of freezing and thawing, in which case they 

 may be scattered about on the surface of the ground. 



The young make their way down the plant head foremost, and so 

 remain until before pupating, when they reverse their position in the 

 flaxseed and are then situated head upward, and thus pass into the 

 pupal stage. Before the fl}^ issues, however, if the flaxseed is not 

 situated conveniently for its escape, the pupa will push itself, if pos- 

 sible, to such a point, and frequently empty pupa skins may be 

 observed protruding from under the sheaths of the leaves. 



The fly itself is not easily observed until one becomes familiar witli 

 its appearance, and this will account for the great variety of insects 

 that are continually mistaken In' farmers for the Hessian fly. Much 

 of this ditticulty may be obviated if farmers will look for an insect 

 like that shown in flgure 1, liut very minute and somewhat resembling 

 a very small mosquito. During warm days, in the egg-laying season, 

 the flies may be observed fl3"ing about in the young wheat, alighting 

 upon the leaves. In cooler days, or in early morning while a heavy 

 dew is on. they will be down among the leaves, or even on the ground. 



LIFE HISTORY. 



At present all indications point to the probability of the Hessian fly 

 being two-brooded, at least during favorable seasons, over its entire 

 area of distribution in the United States. 



In the South the two broods are the most widely separated, while 

 in the North, in the regions of spring-wheat growing, they seem to 

 follow each other in quick succession. 



LIFE nitSTORY IN EEGIONS OF FALL-WHEAT (iROWIXG. 



Throughout the fall-wheat-gi'owing sections the fly passes the winter 

 in the young wheat, mostly in the flaxseed stage, but also to some 

 extent as from two-thirds to full-grown larva. It is difiicult to esti- 

 mate the number of these larva? that will winter over and remain alive 

 until spring, owing to the fact that it is impossible to determine whether 

 they are alive or dead until they begin to decay. But where we have 

 attempted to rear them, even thougli apparently alive, comparativel}" 

 few adults have been obtained, though of course this mortality would 

 probabl}' vary somewhat with the severity of the weather during 

 winter. 



In spring (from March, in Georgia and South Carolina, to May, in 

 Michigan) the flies escape from the flaxseeds and deposit their eggs on 

 the wheat, and the young from these develop to flaxseeds before har- 

 vest, passing the summer in the stubble. The flies from overwintering 

 larvEB come on later; and it is quite probable, also, that some of the 

 very earliest deposited eggs may give rise to adults at about this 



