360 
THE STUDY OF INSECTS . 
strengthened by the development of some extra veins, the 
humeral veins (Fig. 441, h. v.).* 
The larvae of the Lasiocampids feed upon the foliage of 
trees, and are frequently very destructive. 
The family is a small one, less than thirty North Ameri¬ 
can species being known to entomologists. Our more com¬ 
mon ones represent three genera: Clisiocampa (Clis-i-o-cam'- 
pa), which includes the Tent-caterpillars, and Phyllodesma 
(Phyl-lo-des'ma) and Tolype (Tol'y-pe), which include the 
Lappet-caterpillars. 
There are several species of Tent-caterpillars in this 
country. Most of them belong to the Pacific coast; but 
two are common in the East. Of these the most com¬ 
mon one is the Apple-tree Tent-caterpillar, Clisiocampa 
americana (C. a-mer-i-ca'na). This is the insect that builds 
large webs in apple and wild cherry trees in early spring. 
Figure 442 represents its transformations. The moth is dull 
yellowish brown or reddish brown, with two transverse 
whitish or pale yellowish lines on the fore wings. 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 remain 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 keeping together 
and building a tent in which they live when not feeding. 
The figure represents a specimen in our collection. In this 
case the tent was begun near the cluster of eggs. But usu- 
* So far as we know, humeral veins occur nowhere else in the Lepidoptera, 
although in many butterflies vein I of the hind wings is preserved and 
appears like a humeral vein. The humeral veins of the Lasiocampidse do not 
represent any of the primitive veins, but are developed secondarily. 
