154 THE OAK 
Much mischief is effected by the attacks of insects 
of various kinds. ‘The caterpillars of certain moths 
(especially Cnethocampa and Tortrix), for instance, eat 
off the leaves in June, and then form large masses of 
mingled débris, skins, &c., as they pass into the pupa 
stage in July. The denudation of the leaves brought 
Fig. 40.—TZortrix viridana, the green oak-moth, the larvz 
of which eat off the young leaves. (Altum.) 
about by such caterpillars is apt to be very exhaustive 
to the trees, for although they put forth new foliage in 
July and August, it must not be forgotten that these new 
leaves are constructed from materials which should have 
gone to the general stores in the tree, and from which 
new wood, for instance, would have been developed. 
