194 
THE STUDY OF INSECTS . 
fleshy, without joints, elastic or contractile, and are generally 
surrounded at the extremity by numerous, minute hooks 
(Fig. 234) ; they are termed pro-legs. 
Most caterpillars, except the larvae of butterflies, spin 
cocoons (Fig. 235). In some instances, as in case of the 
Fig. 235.—Cocoon of a moth. 
silkworms, a great amount of silk is used in the construction 
of the cocoon; in others the cocoon is composed principally 
