LEPIDOPTERA 257 



and the maxillae are wanting; and the palpi are usually short and woolly. 

 But the most distinct characteristic is found in the wings. The frenulum 

 is wanting, there being instead, as in the giant silkworm moths a largely 

 expanded humeral angle of the hind wings. 



The larvae of the Lasiocampidae feed upon the foliage of trees, and are 

 frequently very destructive. 



Less than thirty North American species are known. 



The apple-tree tent-caterpillar, Malacosoma americdna. — Th'is insect 

 builds large webs in apple and wild cherry trees in early spring. Figure 

 349 represents its transformations. The moth is dull reddish-brown, 

 with two transverse whitish or pale yellowish lines on the fore wing. The 

 figure represents a male; the female is somewhat larger. These moths 

 appear early in the summer. The eggs are soon laid, each female laying 

 all her eggs in a single ring-like cluster about a twig; and here they re- 

 main unhatched for about nine months. This cluster is covered with a 

 substance which protects it during the winter. The eggs hatch in early 

 spring, at the time or just before the leaves appear. The larvae that 

 hatch early feed upon the unopened buds till the leaves expand. The 

 larvae are social, the entire brood that hatch from a cluster of eggs keep- 

 ing together and building a tent in which they live when not feeding. 

 The larvae leave the nest daily in order to feed ; and spin a silken 

 thread wherever they go. The larvae become full-grown early in June; 

 one of them is represented on a partially-eaten leaf in the figure. When 

 ready to transform they leave the trees and make their cocoons in some 

 sheltered place. These cocoons are quite peculiar in appearance, having a 

 yellowish-white powder mixed with the silk. The pupa state lasts about 

 three weeks. 



Another species of the genus Malacosoma found in the East is the 

 so-called forest tent-caterpillar, Malacosoma dis stria. The range of this 

 species extends throughout the United States and Canada. It differs 

 from the preceding species in that the larvae do not construct a true tent. 

 It feeds on the leaves of many forest and fruit-trees, but maple is its 

 favorite food-plant. In other respects its life history is quite similar to 

 that of the apple-tree tent-caterpillar. The moth differs from M. amer- 

 icana in having the oblique lines on the wings dark instead of light; the 

 larva differs in having a row of spots along the back instead of a con- 

 tinuous narrow line; the egg-masses differ in ending squarely instead of 

 being rounded at each end; and the cocoon is more fragile, with less 

 powder, and distinctly double. 



The Great Basin tent-caterpillar, Malacosoma fragilis. — This species 

 is found throughout the northern portions of the Great Basin, extending 

 from the Rocky Mountains to the Cascades and Sierra Nevadas, and has 

 been found in California. It feeds on Ccanothus 

 and many other wild shrubs. 



The California tent-caterpillar, Malacosoma 

 californica, feeds normally on oak but also at- 

 tacks fruit-trees. The caterpillars are orange- 

 colored and about 1 inch long. 



The velleda lappet, Tolype velleda. — The 

 bodv of the moth is milk-white, with a large 

 blackish spot on the middle of its back (Fig. 450) . FlG ' 4S °- _ Tolype velleda - 



That part of this spot which is on the thorax is composed of erect scales, 



