54 OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 
easily seen, especially in winter when the leaves have fallen. These 
bags are made by the larva or worm which lives within them. The 
female moth is wingless, and only leaves the bag in which she passed 
her larval and pupal life after she has deposited her eggs in her empty 
chrysalis skin or puparium. She then falls to the ground and perishes. 
The eggs remain in the bag all winter and hatch in spring into young 
worms, which scatter and at once make new bags, which increase with 
their growth and protect them from the attacks of birds. 
The male moth is a small, black, hairy-bodied creature, with ample 
transparent wings, and escapes from the chrysalis after it is partially 
worked out of the hind end of the bag. This worm is a very general 
feeder, but is, on the whole, more injurious to evergreens than to de- 
ciduous trees. 
This species has several insect parasites. 
3. The White-marked Tussock-moth has a very beautiful hairy larva 
or caterpillar marked with black and yellow and red. The female co- 
coons are to be found during the winter on the trees and upon neigbor- 
ing fences and tree-boxes, and each cocoon is plastered with a number 
of eggs, protected by a white, frothy, glutinous covering. The eggs 
hatch in spring and the young worms feed upon the fresh leaves. The 
males spin their cocoons after three molts and the females after four. 
The moths issue in July, pair and lay eggs for a second brood of worms, 
which im turn transform and bring forth moths. in October, the eggs 
from which hibernate. The male moth is active, with ample wings, 
which are brown, with a conspicucus white spot, while the female is 
pale and wingless, and only crawls out of her cocoon to lay her eggs 
thereon and die. This species is never found on evergreens, and is 
chiefly injurious to elms and maples, and prefers large and old trees 
to young ones because of the greater shelter which they offer for its co- 
coons. In Washington it is yet chiefly confined to our parks, and it 
has not begun to be as injurious as in cities like Philadelphia and Bal- 
timore, where the trees are older and larger. Two probable egg-para- 
sites and seven parasites of larva and pupa are known to me. 
4. The Fall Web worm passes the winter in the pupa state. The 
cocoons are found during the winter principally at the surface of the 
ground, mixed with dirt and rubbish, or in cracks and crevices of tree 
boxes, in fences, and under door steps and basement walls. The first 
moths issue from these cocoons in May, and lay their eggs in flat batches 
on the under side of the leaves. The young worms feed preferably in 
company, webbing first one and then several leaves together, and 
gradually extending their sphere of action until a large part of the tree 
becomes involved. The worms become full grown in July and spin 
cocoons, from which a second generation of moths issue early in August 
and lay eggs, from which the worms hatch, so they are once more in 
force by the latter part of August. This is the species which did the 
damage last year. The parent moth is white, with a varying number 
