12 Insects Injtirioxis to Vegetation. [Jan., 



this theory to be abandoned by its late advocates, from the fact 

 that for four years past, we have met with no farther attempts to 

 sustain it. To us it appears manilest that the lady was widely 

 misled at the very outset of her observations by an error in Mr. 

 Say's account, to wit, that "the perfect fly appears early in June." 

 Were this the case she might well enquire, "Where are the eggs 

 placed? Surely not in the old and dying stalk .... and there is 

 no young wheat growing from June until September." The flies 

 which Miss M. saw in June, 1836, "in countless numbers, hover- 

 ino- over and settling on the ears of wheat," we cannot but sus- 

 pect were the same species which in this section of country ap- 

 pears in such swarms upon the heads of wheat about the middle 

 of June, that it has been for years mistaken hereabouts for the 

 wheat fly or midge. (Vide Quarterly Jour. JigricuUure, vol. ii., 

 p. 238 and 243.) In size and color it does closely resemble the 

 Hessian fly, and might readily mislead any one just commencing 

 their observations. That occasional specimens of the Hessian fly 

 may be taken in June we do not doubt; but that the main brood 

 comes out, deposits its eggs, and disappears, a month earlier than 

 this, we are quite confident, from our own observations as already 

 related, as well as from the testimony of almost every writer who 

 speaks definitely upon this point. Those few larvae which have 

 been found in the centre of the wheat culm, were not unlikely of 

 some other species, since in this particular its habits correspond 

 with those of the Cephus pygmcBus, the Chlorops piimilicnis, &c. 

 That the Hessian fly larva resides in the sheath of the culm, and 

 not in its centre, we feel confident Miss M. has herself become 

 convinced ere this day: — so earnest and candid an enquirer after 

 truth, and one so capable of giving to every fact its due weight, 

 cannot long remain in error, upon a point so susceptible of de- 

 monstration as this. 



Its Parasites. 



It is well known that one of the most effectual means for keep- 

 ino" the Hessian fly in check and preventing it from literally swarm- 

 ing all over our land, has been provided by nature herself. Other 

 insects have been created, apparently for the very purpose of 

 preying upon this, and thus preventing it from becoming inordi- 

 nately multiplied. The world is indebted to Mr. Herrick for much 

 interesting information respecting these insects, the result of his 

 own accurate and patient investigations. As we purpose, should 

 we succeed in more fully tracing out the history of these and oth- 

 er Cecidomyian parasites, making them the subject of a separate 

 memoir at some future day, we refrain from devoting to them any 

 considerable space in the present paper. The general reader, 

 however, will scarcely pardon us, if we omit all allusion to them. 



