180 DISEASES OF THE COTTON PLANT. 
and even when such is the case, tliey may have been blown 
there from the cedars, maples, or other deciduous-leaved 
trees in the woods «n the edges of the plantations. They 
are the more particularly mentioned here, from the fact 
that, if taken in time, they may easily be exterminated on 
deciduous-leaved shade-trees ; for, as I have before stated, 
the female cases contain all the eggs, which may be seen 
in winter hanging on the branches when the leaves have 
fallen, and even are large enough to be distinguished when 
on evergreens. It would therefore require but little trouble 
to pull them off in the autumn and winter, and burn them, 
so that neither males nor females should escape. If this 
course were pursued two or three years in succession, there 
would not be so many complaints in our cities about the 
drop-worms destroying the foliage of the trees. 
The Corn Emperor-Moth. — (Satumia io.) 
The foliage of the cotton plant is also eaten by the 
caterpillar of a large moth. This spiny and stinging 
caterpillar is often found upon the leaf of cotton in Septem- 
ber ; it feeds likewise upon the blades of Indian corn, and 
the leaves of the willow, balsam-poplar, dogwood, and 
many other trees. Whenever one of them is found in a 
field, the plants attacked by it may be easily distinguished 
by their leafless appearance in the midst of the otherwise 
green and flourishing vegetation, as it rarely quits a plant 
before it is completely denuded. Often, however, those 
which have lost their leaves from the rust present much 
the same bhghted appearance; but, in this case, the 
numerous yellow, withered leaves, which are scattered on 
the ground, at once indicate the disease. 
The thorny spines with which these caterpillars are 
