260 
[Senate 
1829 (p. 323), he corrects the latter part of the above statement, and 
says, 11 At that time I did not know that a yellow fly had deposited 
the eggs within the glume, which became maggots. Observing 
numbers of black flies on the ears of wheat, T believed they had been 
the produce of the caterpillar. I have this season, however, observ¬ 
ed the yellow fly (described by Rev. W. Kirby) deposit its eggs in 
the wheat-ear,” etc. I notice this more particularly, because the 
farmers in this vicinity, with scarcely an exception, have fallen into 
the same error, and to this day suppose a small black fly, of the fam¬ 
ily Muscidce, which occurs abundantly in wheat-fields, to be the real 
wheat-fly. 
Mr. Patrick Shirreff, of East-Lothian, gives, in the same volume 
of Loudon’s Magazine, pages 448 - 451, an excellent and very accu¬ 
rate summary of the habits and transformations of the same insect, 
the result chiefly of his own observations. For a concise account, 
this is not surpassed by any that has fallen under my notice. 
Still more recently, this subject has been investigated by the Rev. 
J. S. S. Henslow, Prof, of Botany in the University of Cambridge, 
whose valuable “ Report on the diseases of wheat” forms the first 
article in vol. ii. of the Journal of the Royal Agricultural Society of 
England. And in the same Journal for the present year (vol. vi. p. 
131. plate M.) an admirable production is inserted from the pen and 
graver of that accomplished naturalist, John Curtis, F. L. S., giving 
much more accurate and precise descriptions and delineations of the 
wheat-fly, in the different stages of its existence, than any that had 
previously appeared. To it I am particularly indebted for such 
characters as enable me to say without a doubt, that the clear-winged 
wheat-fly of America is identical with the English Cecidomyia Tri- 
tici. 
In closing this summary of the notices of the wheat-fly abroad, I 
would allude to what has occurred to me as perhaps true in the his¬ 
tory of this insect, to wit, that it has somewhat regular periods of re¬ 
curring in such numbers as to become a pest to the agriculturist. 
Thus, it is manifest from Mr. Gullet’s account that it was abundant 
for a few years previous to 1771. So destructive was it then, that 
he pronounces “ these small insects —the wheat crop’s greatest ene¬ 
my.” After an interval of twenty-five years, it is again observed 
plentifully for three or four years, and in different districts, by Messrs. 
