DISEASES OF THE COTTON PLANT. 237 
decrease of their natural food, the lady-birds also disappear 
and migrate to neighboring plantations in search of a fresh 
supply of nutriment. I have actually known several 
planters who have caused them to be destroyed by their 
field hands, when and vvherever found, and who complained 
that their plants were still destroyed by the aphis, or cot- 
ton louse. This was only to be expected, as they had de- 
stroyed the natural enemy of the louse, and sufFei*ed the 
pests themselves to breed in peace and safety. I have seen 
the larvae of the lady-bird as late as the 18th of November, 
in Georgia, still busy exterminating the aphis. The yellow, 
oleaginous fluid, which is emitted by this insect when han- 
dled, has a powerful and disagreeable odor, and is men- 
tioned by Westwood, m his " Modern Classification of In- 
sects," as having been recommended as a specific for the 
toothache. 
It may be remarked, however, that there is a much 
larger species of this insect which does considerable dam- 
age to the leaves of cucumbers, melons, squashes, etc., as 
both larvae and perfect insects devour the leaves and eat 
holes in them, so as sometimes totally to disfigure and de- 
stroy the plants. 
The perfect insect measures nearly half an inch in 
length, and is of a yellow color, with twelve large and 
small black spots on the wing-cases, and four small black 
spots on the thorax ; it can be very easily distinguished, 
however, from its beneficial congener, both by size and 
color, the useful lady-bird being only about the sixth or the 
seventh of an inch in length, and of a bright-red or almost 
scarlet color, with black spots, while the injurious insect is 
much larger, measuring nearly half an inch in length, and 
being of a light-yellow color, spotted with black. 
