8 THE HESSIAN FLY IN THE UNITED STATES. 
have been well founded, for while absolute proof of introduction at that 
particular time and place is wanting, the evidence all goes to show that 
the insect was introduced from Europe at very nearly that period, and 
it evidently must have been brought in straw used for packing or 
baling. 
Dr. Fitch gives an exhaustive summary of the early appearances and 
spread of the insect from the point where first observed. These indi- 
cate a spread from Long Island into adjacent territory at a rate approxi- 
mating 20 miles each year, and Packard has compiled a detailed table 
showing the time of appearance of the pest in each of the States where 
it is known to occur. The first scientific description by Say (117) in 
1817 is rather exceptional, especially for the scientific descriptions of 
that time, in that it contains a description of the larvre as well as of the 
adult forms, some details of life history, and remarks on its economic 
importance. This shows clearly how fully its injuries must have been 
appreciated at the time, a recognition which was emphasized in its spe- 
cific name, destructor. 
Say's description and account must, however, have had limited pub- 
licity, for years later there appeared in no less prominent a journal 
than Silliman's American Journal of Science an article by a Dr. Muse 
which purported to give a true account of the pest, but which contains 
many serious errors, the insect being referred to the Aphides, and the 
author evidently unaware of the more careful description and reference 
of Say. The article, however, contains some important details of life 
history and emphasizes the importance of destroying volunteer wheat 
in stack yards as a measure of control. 
Dr. Fitch's elaborate monograph appeared in 1847 and the articles 
by Dr. Packard in 1878 and 1880. 
At about this time, between the years 1878 and 1887, there occurred 
a somewhat lengthy discussion between Dr. H. A. Hagen (16-47) and 
Prof. C. V. Eiley (108-109) as to whether this pest is of native or for- 
eign origin, but no economic question was involved and it is unneces- 
sary to discuss their papers here. 
During the years 1887 to 1890 Professor Forbes, State entomologist 
of Illinois, devoted much of the effort of his office to a study of this 
pest, and many interesting and valuable facts were gathered concern- 
ing the life-history limits, especially the midsummer condition of the 
insect. The important point was determined that there may be three 
or even four broods in a year, dependent upon climatic or food conditions. 
Prof. F. M. Webster has contributed a number of observations pub- 
lished in experiment station bulletins of Ohio and Indiana and in Insect 
Life. 
In other countries the insect has received of late years considerable 
attention. On its appearance in England it was studied by Miss 
Ormerod (84-85) and by Messrs. Enoch (25-26) and Whitehead (140). 
In 1887 Prof. K. Lindemann (60), of Moscow, made a careful study 
