The Moths and Butterflies 



385 



Much larger moths are the Cossidae, or carpenter-moths, with slender, 

 smooth, spindle-shaped bodies and long, narrow-pointed, strong wings like 

 those of the hawk-moths (Sphingidae). The larvae are wood-borers, bur- 

 rowing about in the heart-wood of locust- and other shade-trees and also of 

 apple-, pear-, and other fruit-trees. The moths are mostly gray, vaguely 

 patterned with white and blackish, although a few are conspicuously black- 

 and-white spotted. They have no proboscis and hence can take no food. 

 The moths fly at night and lay their eggs on the bark of the trees, the hatch- 

 ing, grub-like, naked larvae burrowing into the hard wood, where they live 

 for from two to four years, when they make in their tunnel a thin cocoon 

 of silk and chewed wood to 

 pupate within. When ready 

 to transform, the pupa 

 wriggles along the tunnel 

 to its opening, so that the 

 issuing moth finds itself in 

 free air. The locust-tree 

 carpenter-moth, Prionoxys- 

 tus robinice (Fig. 549), or 

 goat-moth, so called from 

 its curious offensive odor, 

 expanding T inches (males) 

 to 2^ inches (females), has 

 gray wings with irregular 

 black lines and spots in 

 the female, and darker 

 fore wings and yellowish 

 hind wings in the male. 

 Its larvae feed on locust- 



FIG. 548. Venation of a Cossid, Prionoxystus robinia. 

 cs, costal vein; sc, subcostal vein; r, radial vein; 

 m, medial vein; c, cubital vein; a, anal veins. (After 

 Comstock; enlarged.) 



trees and are often abun- 

 dant enough to do much injury. The wood leopard-moth, Zeuzera pyrina, 

 is strikingly spotted with black on a white ground color, and is common in 

 certain eastern cities, its larvae infesting maples and other shade-trees. On 

 the Pacific coast the poplar carpenter-moth, Cossus populi, with whitish 

 fore wings shaded all over with blackish and irregular black lines, and hind 

 wings yellowish gray, growing darker at the outer margin, is common, its 

 larvae infesting poplars and cottonwoods. There are only twenty species 

 in North America belonging to this family. 



Familiar curiosities of entomology are the moving bags of silk and bits 

 of twigs and needles occasionally found in cedars, firs, and arbor vitas. The 

 "worms" which make these bags and carry them around, with all the body 

 inside except the projecting head and thoracic legs, are the larvae of the 



