THE TUSSOCK MOTH 
167 
and providers* As the Tussocks devour the leaves of 
the shade trees, it is satisfactory to reflect that tiny 
parasites are devouring them* Only a few will survive 
to fulfil their life mission* 
They grow by coming out of themselves — by 
casting off their outer covering, head, legs, plumes, 
and tufts of hair* From the inert larva thus cast off 
another emerges, with new head, legs, tufts, decora- 
tions, and markings, larger and brighter than the 
outer form that surrounded it* This change takes place 
two or three times during the few weeks of larval 
existence, and then the full-grown Caterpillars spin 
themselves grey, comfortable cocoons for the brief 
sleep of their pupal state* Some find a comfortable 
place in the cloth bands set about the trees to entrap 
them ; but of the pupae thus collected and burned 
the great majority are already doomed to death by 
parasites — the little beneficial insects thus mistakenly 
destroyed* It is not in human affairs alone that we 
injure ourselves and our friends by the pursuit of 
our supposed enemies* 
Some of the well-fed larvae are too indolent to 
descend the trees, and sleep in the upper branches, 
but the more adventurous make a limited migration 
from tree to tree* Females choose the trees which will 
supply food for their next season's brood, while the 
males, rejoicing in the prospect of winged flight, are 
satisfied with any crevice in a fence or wall* The 
