116 MISC. PUBLICATION 273, U. S. DEPT. OF AGRICULTURE 
in such numbers as to become aggressive in their attacks on health 
living trees. However, such outbreaks are usually of short duration 
and seldom last more than one season. The most frequent damage 
FIGURE 56.—The typical galleries of the Oregon pine engraver score the sapwood. 
is in the killing of young replacement trees from 2 to 8 inches in 
diameter and the top-killing of older trees. 
The adults are reddish brown to nearly black, about one-sixth of 
an inch in Jength, and with four small teeth along the margins on 
each side of the elytral declivity. A typical sample of their work 
eo eee Se = ee SS ore ————_ ~— 
