372 
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Brief Summary of the preceding History. 
The Hessian fly (Cecidomyia destructor of Say,) is a European 
insect, and has been detected in Germany, France, Switzerland and 
Italy, where it at times commits severe depredations upon the wheat 
crops. Its ravages are alluded to so far back as the year 1732. It 
was brought to this country, probably in some straw used in pack¬ 
age by the Hessian soldiers, who landed on Staten and the west end 
of Long Island, August, 1716, but did not become so multiplied as 
to severely injure the crops in that neighborhood, until 1779. From 
theme as a central point, it gradually extended over the country in 
all directions, advancing at the rate of from ten to twenty miles a 
year. Most of the wheat crops were wholly destroyed by it within 
a year or two of its first arrival at a given place, and its depreda¬ 
tions commonly continued for several years, when they would near¬ 
ly or quite cease ; its parasitic insect enemies probable increasing to 
such an extent as to almost exterminate it. It is frequently reap¬ 
pearing in excessive numbers in one and another district of our 
country, and in addition to wheat, injures also barley and rye. 
There are two generations of this insect annually. The eggs re¬ 
semble minute reddish grains, and are laid in the creases of the up¬ 
per surface of the leaf, when the wheat is but a few inches high, 
mostly in the month of September. These hatch in about a week, 
and the worm crawls down the sheath of the leaf to its base, just 
below the surface of the ground, where it remains, subsisting upon 
the juices of the plant, without wounding it, but causing it to turn 
yellow and die. It is a small white maggot, and attains its growth 
in about six weeks. It then changes to a flax seed like body, with¬ 
in which the worm becomes a pupa the following spring, and from 
this the fly is evolved in ten or twelve days. The fly closely re¬ 
sembles a musquitoe in its appearance, but is a third smaller, and 
has no bill for sucking blood ; it is black, the joints of its body be¬ 
ing slightly marked with reddish. It appears early in Ma^,lays its 
eggs for another generation and soon perishes. The worms from 
these eggs nestle at the lower joints of the stalks, weakening them 
and causing them to bend and fall down from the weight of the 
head, so that towards harvest, an infested field looks as though cat¬ 
tle had passed through it. 
