The Moths and Butterflies 
3 8 5 
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 1J inches (males) 
to 2j 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- 
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 vitae. 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 
Fig. 548.— -Venation of a Cossid, Prionoxystus robinice . 
cs, costal vein; sc, subcostal vein; r, radial vein; 
m, medial vein; c, cubital vein; a, anal veins. (After 
Comstock; enlarged.) 
