affecting the Corn-Crops. 
139 
and that Say's C. destructor, called the Hessian fly, is ditFerent 
from either.* The female of the American species lays in the 
autumn not more than eight eggs, which are introduced by her 
ovipositor between the sheath and the stem, close to the base, 
"where the larvae feed as soon as they hatch, and are said to live 
through the winter with their heads downward ; but the mischief 
they cause is not discoverable until the wheat is more advanced. 
A parasite, called by Mr. Say Ceraphron destructor, but Avhich 
may possibly be a Pteromclas in the opinion of Mr. Westwood, 
though smaller than the Cecidornyia, proves so formidable an 
enemy, by depositing its eggs in the larvae, that few of them be- 
come pupae ; otherwise, Mr. Say believes that their wheat-crops 
would be totally annihilated. KoUar also found the majority of 
his pupae so full of a similar parasite that he felt convinced the 
crops would not be attacked by the Avheat-midge the following 
year; which prediction was completely veiitied. I have been led 
to give a more extended sketch than I intended of the North Ame- 
rican and European " Hessian flies," from my conviction that two 
species at least have been confounded by Kollar and other wi iters, 
owing to their similar economy ; and it will be as well to designate 
our species as 
The British Wheat-midge — Cecidomyia tritici, Kirby. 
The alarm we have already alluded to in the last century pro- 
duced good effects, by inducing many talented men to investigate 
the subject in order to allay the public anxiety; and thus, amongst 
other noxious insects, we obtained the natural history of the wheat- 
midge, as it is now called, and little of importance has been added 
of late regarding its transformations. It will now be my object to 
lay before the Society the leading points of these contributions, so 
connected as to enable the agriculturist to understand the economy 
of this destructive little animal, and to supply materials for per- 
fecting its history as opportunities may offer; for I am satisfied 
that at a future day these are subjects which will not be found un- 
interesting or unprofitable to the agriculturist. 
In May, 1796, a paper was read before the Linnaean Society by 
Mr. Marsham, the secretary,! in which he stated that Mr. Long, 
who farmed land in Hertfordshire, had detected an insect amongst 
the wheat, towards the end of July, which threatened to do much 
mischief, attacking from one to several grains in an ear. It was 
easily discovered from such grains appearing yellow or ripe, whilst 
the unaffected grains in the same ears were perfectly green. " On 
opening those grains that seemed diseased," Mr. Marsham " found 
* Trans. Ent. Soc, vol. i. p. iv and v. 
t Trans. Linn. Soc, vol. iii. p. 242. 
