THE HESSIAN FLY IN THE UNITED STATES. 
INTRODUCTION. 
It is now seventeen years since any comprehensive treatise on the 
Hessian fly in America has been published. In the meantime so many 
important facts have been learned concerning the life history, food 
habits, and parasitic enemies of this important pest that such a treatise 
is urgently demanded. While the main object in such a review is the 
bringing together of these recent contributions with the important 
deductions with regard to treatment which follow, the fact that the 
elaborate essays by Drs. Fitch and Packard, so exhaustive for their 
time, are inaccessible to a great majority of farmers and even to many 
students, is a sufficient reason to present the details known concerning 
this insect. 
In the following presentation the attempt has been to condense this 
information into as compact form as possible and to devote the greater 
part of the space to the questions having most practical importance 
and to facts giving the essential basis for remedial measures. In pre- 
paring the work the writer has been indebted to the exhaustive papers 
by Fitch (30)* and Packard (90) and, for recent contributions, particu- 
larly to the important papers by Forbes (34-39), Webster (137), Linde- 
mann (60), and MarchaJ (71). 
A list of the more important articles referring to this insect is given 
at the end of the paper, and will indicate the literature available, and 
avoid the necessity of too frequent references in the text. I am 
indebted to Dr. L. O. Howard for many notes and to Profs. S. A. Forbes 
and F. M. Webster for material. 
IMPORTANCE AND EARLY HISTORY. 
The Hessian fly probably ranks next to the chinch bug as a farm pest 
in the United States, and its ravages in other countries have long been 
known and appreciated. While its first scientific description was by 
Thomas Say in 1817, it had been for many years recognized as a pest 
in wheat and had received in this country the popular name of Hessian 
flyin the belief that it had been introduced by Hessian soldiers during 
the war of the Revolution. This belief, as we shall see later, seems to 
* The numbers after authors" names correspond to numbers in a bibliographical list 
which is appended. 
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