HESSIAN FLY. 
25 
autumn brood is dead, is a most important precaution, but, as it 
appears to be safe if put in after the beginning of October, this point 
is usually met in this country without special arrangements. 
Dressings, and mechanical measures, as rolling, &c., may or may 
not answer, according to circumstances. 
All measures to secure good hearty growth, such as may carry the 
moderately injured plants through attack, are very desirable. 
So is rotation of crop, as the fly only attacks certain cereals 
specified. 
Strong-stemmed corn is less liable to attack than kinds of which 
the outside is more readily injured by the maggots. 
The above methods of treatment mitigate the violence of the 
attack, and if in the coming season we find this injury, which has 
now for over a hundred years caused from time to time such devas¬ 
tating loss in America, has settled down here, we cannot do better 
than study in full detail the reports of observation and agricultural 
treatment which have been found to mitigate the evil. 
But meanwhile it is most urgently to be considered. Where did 
THE ATTACK COME FROM ? As in the hundred years and more that it 
has been in America, and about half that time that it has been known 
in Europe, we have no records of its presence as a crop-pest; and 
plenty of records of it not being present it is reasonable to suppose 
that there has been some special circumstance which has not occurred 
before to which we owe its presence. To find what this is would be 
to find how to free ourselves from a most dangerous crop-pest, and if 
all concerned would examine into the various ways in which it can 
have been conveyed on the land, and will continue this watch and 
report on it in the coming season, we may hope to learn the source of 
the evil. 
I will venture to add that I shall have pleasure in receiving any 
communication on the subject, or samples of infested grain, and also 
samples of winter wheat or barley considered to be infested, and in 
giving all information that lies in my power on the subject. 
Bibliographical References. 
The following list gives the titles of some of the publications in 
which information will be found regarding the original identification 
of the species of Cecidomyia destructor' by Thomas Say, and likewise 
regarding its habits, history, and distribution in America and Europe, 
and means of prevention and remedy. The most important and 
serviceable of the papers are those of the U.S.A. Department of 
Agriculture, and the papers by Dr. B. Wagner :— 
Some account of the insect known as the Hessian Fly. By Thomas Say. 
Journal of Academy of Nat. Sciences, i., pp. 45 - 48, 1817. 
