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 PJiyllodesina 

 (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 Lasiocampids do not 

 represent any of the primitive veins, but are developed secondarily. 



