716 NEW YORK STATE MUSEUM 
was sown late, and in early July many fields in Genesee county 
were badly infested. The pests were near the ground in the 
latest sown barley and in that early sown, they occurred from - 
10 to 12 inches from the ground, showing at least, that the insect | 
breeds by preference in the soft growth and inferentially that 
it thrives only indifferently in the older, harder growth. This 
relation between the rank succulent growth of the grain and 
injury by the Hessian fly was further shown on one hilly patch 
of wheat. There was considerable grain on the gravelly, com- 
paratively dry knolls while in the more moist, probably poorly 
drained gullies the stalks of wheat were very scattered. Here 
seems to be a possible reason why a variety of wheat may be 
comparatively “fly proof” in one section and not in another, 
since its apparent resistance may depend very largely on the ; 
relative hardness or maturity of the stalk at the time the flies 
appear and deposit eggs and this might easily vary in widely 
separated sections during the same season. Another generation 
might easily have developed, so far as time is concerned, between 
the middle or the latter part of July, at which date the above 
mentioned brood attained its maturity, and the period when the 
normal fall brcod appears, which is usually before September 
20 in New York. The above shows that four generations and 
possibly more may develop in a season, but it should be distinctly 
understood that, as a rule, only two full broods are developed, 
and that the intermediate summer generations are usually very 
limited and that their development is very dependent on weather 
and crop conditions. 3 
Emergence and flight. This is an exceedingly important mat- 
ter, because on its correct understanding rests one of the most 
successful methods of preventing injury by this pest. This, 
like the development of the summer generations, is dependent 
on weather conditions. The following rules will aid in under- 
standing the situation: 
1 The flies may remain an indefinite period in the “ flaxseed ” 
or pupal stage during dry weather. ~ 
2 “Flaxseeds” or pupae are very likely to develop tlies in 
large numbers during a period of damp, warm weather. 
