112 
AGRICULTURAL REPORT. 
and nearly black; on the head were three ocelli; the thorax was 
black ; the wings transparent., of a rather yellowish tinge, veined 
with black, and having a distinct black mark on the outer margin 
of the upper pair ; the first joint of the hind-leg was comparatively 
large, thick, and of a brownish color; the thighs were also brown; 
the tibia;, black, with a broad white band in the middle; the tarsi 
were white, tipped with black; and the ovipositor protruded more 
than the tenth of an inch. The male presented much the same ap- 
pearance as the female, but was more slender in form. 
THE SMALLER ICHNEUMON-FLY. 
( Ichneumon ?) 
The ichneumon-fly, which destroys the aphis, or louse, so very 
injurious to the cotton-plant, is a minute insect, not quite the twen- 
tieth of an inch in length. The head and thorax are black, and the 
legs and abdomen of a yellowish color. Although so extremely 
6mall as to be unobserved, it is constantly engaged in exterminating 
the cotton-lice, myriads of which it destroys by preying upon their 
vitals. The female fly lays a single egg in the body of each louse, 
which, -when hatched, becomes a grub. This grub devours the inte- 
rior substance of the aphis, leaving only the grey and bloated skin 
clinging to the leaf. This skin serves the young larva for a shelter, 
where it remains until it changes into the perfect fly, when it emerges 
from a hole gnawed through the back, and issues forth furnished 
with four transparent wings, to recommence the beneficial labor of 
depositing more eggs in the surrounding colonies of lice on the neigh- 
boring plants. 
The number of lice destroyed in this way can be more fully appre- 
ciated by observing the multitude of empty grey and bloated skins, 
more or less scattered over the cotton-plants infested, each skin hav- 
ing a hole in the back through which the perfect fly has escaped. 
THE SYRPIIUS. 
The larva; of this syrphus (PL X. fig. 5) are found wherever 
aphides, or plant-lice, abound, and present the appearance of small, 
yellowish-white naked maggots, or grubs, of about a fifth of an inch 
in length. Their color is brown, with six distinct yellow spots on the 
first three segments of the body, and the sides are also marked on 
the margin with yellow ; the body is somewhat hairy. The head is 
armed with powerful jaws, and gradually tapers to a point, while the 
tail terminates abruptly as if cut off. 
The parent fly deposits her eggs amongst the lice, in order to 
insure an adequate supply of food to each grub. These eggs are 
soon hatched by the heat of the sun, and the young grub immedi- 
ately commences crawling about the leaf; and, being blind, inces- 
santly gropes and feels around on either side in search of cotton or 
plant-lice, its natural food, one of which, being found by the touch, 
is instantly seized, elevated above the surface of the leaf on which it 
