154 
THE SCOLYTID BEETLES. 
punctured, becoming finer toward base, the sides slightly narrowed 
toward the head, but not strongly constricted; the elytra with coarse, 
transverse to oblique rugosities between distinct to obscure rows of 
punctures; the declivity convex, with moderately deep grooves, and 
the intervening spaces slightly convex and roughened; the entire 
body sparsely clothed with long hairs. (See fig. 97.) 
It attacks the living bark on injured, dying, healthy, and felled pine 
and spruce in eastern United States and Canada, north from the 
mountains of North Car- 
olina, westward to the 
Pacific coast, and south- 
ward from British Co- 
lumbia into Mexico. The 
parent beetles excavate 
broad, somewhat irregu- 
lar, winding, longitudi- 
nal egg galleries (fig. 98) 
through the inner bark 
and groove the surface 
of the wood. The eggs 
are placed in groups or 
masses at intervals along 
the sides of the galleries. 
The stout, yellowish- 
white, cylindrical larva?, 
with reddish heads and 
stout spines on the dorsal 
plates of the last ab- 
dominal segments, do 
not make separate larval 
mines, but all feed to- 
gether and eat out cavi- 
ties in the inner bark from 
a few inches square to 
several feet square (see 
fig. 98). They transform 
to pupae and adults in 
separate or closely joined cells in the inner bark, or inner portion 
of the outer bark, or in mines extending from the social cham- 
ber. The broods work independently of other species and occupy 
and separate the bark around the base of trees and stumps (see 
Hg. 99), often extending their work for a foot or more onto the 
roots beneath the surface, and the broad larval chambers are often 
filled with semiliquid resin, without injury to the occupants. The 
Yig. 97.— The red turpentine beetle (Dcndroctonus valens): 
Adult. Greatly enlarged. (Authorsillustration.) (Seealso 
fig. 4, larva: rig. 5. pupa. 1 ) 
