810 
ANNUAL REPORT OF NEW YORK 
HIDOE. PARASITES. THE LARVA PARASITE’S OPERATIONS. 
color ; its abdomen is scarcely larger than the thorax, somewhat 
flattened and obovate; its -legs are pale dull yellow with the 
shanks very much thickened towards their tips. Its length is 
0.05, or to the ends of its wings, 0.07. 
. Mr> Kirb y S ives the following interesting account of the opera- 
tmns of this insect when depositing its eggs. “ To see our little 
Ichneumon deposit its egg in the caterpillar of the wheat fly is a 
very entertaining sight. In order to enjoy this pleasure I placed 
a number of the latter upon a sheet of white paper, at no great 
distance from each other, and then set an Ichneumon down in the 
midst of them. She began immediately to march about, vibrat¬ 
ing her autemue very briskly ; a larva was soon discovered, upon 
which she fixed herself, the vibratory motion of her antennal 
increasing to an intense degree ; then bending her body obliquely 
under her breast, she applied her anus to the larva, and during 
the insertion of her aculeus and the depositing of the egg her 
antennas became perfectly still and motionless. Whilst this ope¬ 
ration was performing, the larva appeared to feel a momentary 
sensation of pain, for it gave a violent wriggle. When all was 
finished, the little Ichneumon marched off to seek for a second, 
which was obliged to undergo the same operation, and so on to 
as many as it could find in which no egg had been before depo¬ 
sited, for it commits only a single egg to each larva. I have 
seen it frequently mount one which had been pricked before, but 
it soon discovered its mistake and left it. The size of it is so 
near that of the wheat-fly, that I imagine the larva of the latter 
could not support more than one of the former, and therefore, 
instinct directs it to deposit only a single egg in each; besides, 
by this means one Ichneumon will destroy an infinite number of 
larvm.” 
Mr. ShirrefT reports that he saw one of these parasites sting a 
larva a second time. The maggot writhed in seeming agony and 
straggled from the wheat ear on to his thumb nail, where it was 
again stung, three times by the same fly, and in another encoun¬ 
ter both fell to the ground. But I cannot think an egg was 
inserted only in the puncture first made. The other stings were 
very likely made to drive the larva to wriggle and fall to the 
ground, Jest if it remained, exposed as it then was, some other 
enemy should happen along and devour it and the offspring of 
the parasite with it. It is much to be regretted that this deeply 
