260 [Senate 



1829 (p. 323), he corrects the latter part of the above statement, and 

 says, " At that time I did not know that a yellov»^ fly had deposited 

 the eggs within the glume, which became maggots. Observing 

 numbers of black flies on the ears of wheat, I believed they had been 

 the produce of the caterpillar. I have this season, hov/ever, 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^ 



