INSECT ENEMIES OF EASTERN FORESTS 417 
The cocoon is oval, about 1 inch long, and composed exteriorly of 
coarse, whitish silk surrounding the tougher parchmentlike lining. A 
yellow, powdery substance is mixed with the silk. 
This moth is generally distributed throughout the United States 
east of the Rocky Mountains. The foliage of the wild cherries and 
apple is most favored as food, but other plants such as plum, peach, 
hawthorn, pear, rose, and some of the deciduous forest and shade trees 
are often attacked, particularly when the supply of favored food 
becomes exhausted. 
Ba 
FicureE $85).—Tent caterpillars. A, Malacosoma americana: a, Adults; b, egg cius- 
ter; c, tent; d, caterpillars; B. M. disstria: a, adults; 6, egg cluster; c, cater- 
pillars. (Courtesy Conn. Agr. Expt. Sta.) 
There is one generation a year. The eggs usually begin to hatch 
during the first warm spell in spring, as soon as the wild-cherry leaves 
begin to unfold or a little earher, The larvae are gregarious and soon 
begin to construct their tent of silk in a nearby crotch, enlarging it 
as they grow (fig. 85, A, ¢). During cloudy and rainy weather the 
larvae usually remain within the nest, but when the weather is favor- 
able they go out on the foliage and feed at regular intervals, spinning 
threads of silk wherever they go. In about 6 weeks after hatching 
they become full grown and transform to the pupal stage, which lasts 
from 10 days to 2 weeks. In the Northeastern States hatching usually 
begins about the second or third week in April, the larvae generally 
