DISEASES OF THE COTTON PLAOT. 
165 
mistake might the more easily be made by any person 
who had not himself observed the eggs when hatching, as 
that of the lace -wing fly is held by such a filament, and, 
moreover, is found in smiilar situations on the leaves, but 
generally with or near a colony of plant lice, where the 
instinct of the parent lace-wing fly teaches it to deposit its 
eggs, and thus provide for a supply of fresh food for the 
young larvae, which feed upon and destroy millions of the 
cotton-lice. There is a great diff"erence also between the 
eggs of the caterpillar moth and those of the boll-worm 
moth, the first being, as before stated, round and flattened 
in shape, and green in color, whereas those of the boll- 
worm moth are not flat, but more of an ovoid shape, and 
of a dirty-yellowish tinge. I cannot state exactly what 
time is required to hatch the eggs after they have been 
laid by the parent fly, as I could not succeed in procuring 
any from the moths hatched and kept in confinement, 
although carefully preserved for the purpose. Dr. Capers 
says that it requires from fourteen to twenty days ; but the 
eggs I found in the fields invariably hatched within a week 
from the time they were brought into the house. How- 
ever, this must depend a great deal upon the state of the 
atmosphere and the warmth of the season. The young 
caterpillars, when hatched, very soon commence feeding 
upon the parenchyma, or soft, fleshy part of the leaves, and 
continue to do so until they become suflnciently large and 
strong enough to eat the leaf itself. They are able to 
suspend themselves by a silken thread when shaken from 
the plant. They change their skins several times before 
attaining their full growth, when they measure from one 
and a half to nearly two inches in length. The first brood 
of caterpillars, in August and September, were all of a green 
color, with narrow, longitudinal, light stripes along each 
