234 DISEASES OF THE COTTON PLANT. 
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 immediately commences crawling about 
the leaf; and, being blind, incessantly 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 is quietly feeding, in order to prevent the strug- 
gling victim from using its feet, or clinging to the leaf when 
endeavoring to escape from its voracious destroyer. After 
piercing the living insect the grub leisurely sucks out the 
juices, throws away the empty skin, and recommences feel- 
ing about in search of another, which, when found, is 
treated in the same way. When ready to change, the 
syrphus maggot fastens itself to a leaf or stalk, by means 
of a glutinous secretion from its own body, and the outer 
skin contracting into a pear-shaped case, soon hardens by 
exposure to the air, and the pupa is formed inside. 
After a few days, during the heat of summer, the per- 
fect fly emerges from a hole, at the blunt end of the case, 
to lay eggs amongst the colonies of lice on the neighboring 
plants. The perfect fly is about seven-tenths of an inch 
across the wings, which are two in number, and transparent. 
The body is generally more or less banded with brown, 
or black and yellow, and appears like that of a diminutive 
wasp. This fly has a peculiar habit of hovering on the 
wing, apparently without motion or exertion, during the 
heat of the day, near or over flowers, and when disturbed 
it darts away with great swiftness ; but, if the object that 
