REPORT OF THE STATE ENTOMOLOGIST I9i2 37 
to be somewhat more seriously damaged than others. Mr Henry 
D. Flach, of Attica, reports considerable damage in that section of 
the county though not all fields were injured; the loss in some 
amounted to 30 per cent. 
Food plants. The Hessian fly was early recognized as a pest 
of wheat, rye and barley, and despite the fact that there are occa- 
sional records of its occurrence in timothy and other grasses and 
grains, there is no authentic evidence of its living in anything else 
except the grains named above and quack or witch-grass, A gro - 
pyronrepens. This restriction in food plants is of consid- 
erable importance, since it materially simplifies the problem of 
control. 
Life history. There are two generations in this latitude norm- 
ally, though supplemental ones may occur. The adult fly deposits 
from 100 to 150 eggs, according to Marchal, placing them between 
the ridges on the upper surface of the blades of young wheat. 
Midges of the spring brood occasionally thrust their eggs beneath 
the sheaths of the lower leaves. 
The flies may occur any time after wheat is up and _ possibly 
between killing frosts. The eggs hatch in about four days and 
the maggots then make their way down the leaf to the base of 
the sheath. They do not burrow but lie next the stem and 
absorb nourishment from the adjacent soft tissues which gradually 
become depressed and give way as the insect develops. The mag- 
gots are usually found in the fall close to the roots of winter wheat 
and at or beneath the surface of the soil, while in the spring they 
are more common about the second or third joints. The larval 
transformations occupy about twenty days, though their duration 
is much affected by weather conditions. The length of the pupal 
stage is exceedingly variable and greatly modified by the precipita- 
tion. Cold or heat and dryness tend to lengthen, and heat and 
moisture to shorten the duration of the different stages, especially 
the pupal. The winter is passed in the flaxseed or pupal stage, 
the spring brood of flies emerge in April or May and in turn de- 
posit eggs on the more luxuriant leaves and another life cycle may 
be completed in about thirty days. 
Number of generations. The short life cycle permits a number 
of broods in one season and apparently there may be as many 
generations as weather and food conditions permit. We may ex- 
pect constant breeding during the growing season if continued damp 
