54 
THE STUDY OF INSECTS. 
The larval stage is devoted to growth/ the sole business 
of a larva being to eat and grow. All molting, because of in¬ 
creased size, is done in the larval stage, later molts are 
simply for change of shape. 
The Pupa .—This is the third stage in the life of an in¬ 
sect, and is ordinarily a period of inaction, except that rapid 
and wonderful changes go on within the body. Very few 
pupae, like those of mosquitoes, are active. Usually pupae 
have no power of moving 
around, but many of them can 
squirm when disturbed. When 
the last skin of the larva is 
thrown off the pupa is re¬ 
vealed ; it is an oblong object, 
Fig. 65.-A pupa of a large moth. frequently apparently 
headless and footless. In many pupae the skin is a shiny 
covering like porcelain. If a pupa be examined closely the 
antennae and legs and wings may be seen ; these are folded 
up closely and soldered to the breast in the case of tne 
moths and butterflies (Fig. 65), but free in case of the bees, 
ants, and beetles. 
The Chrysalis .—This term is often applied to the pupa of 
a butterfly. The word is derived from a Greek word mean¬ 
ing gold, and came into use because of the golden dots and 
markings on many of the butterfly pupae. 
The Cocoon .—Many larvae, especially those of moths, 
when full grown, spin about the body a silken case, so that 
when they change to helpless pupae they may be protected 
from enemies, and from rain and snow; these silken cases 
are called cocoons. They are frequently made within a 
rolled leaves (Fig. 66), or beneath grass and rubbish on the 
ground, or in cells below the ground. Some hairy caterpil¬ 
lars make cocoons largely of their own hairs, which they 
fasten together with a film of silk. 
The Nymph .—The terms larva and pupa are only ap. 
plied to the early stages of those insects that have a com- 
