128 MISC. PUBLICATION 273, U. 8S. DEPT. OF AGRICULTURE 
trees. These belong to the same genera that are met with in pines 
and firs. | 
The Sitka spruce engraver (/ps concinnus Mann.) attacks the | 
bark of living, dying, or felled Sitka spruce along the coast of 
Oregon and northward to Alaska. No reports have been received 
of its having done more than nominal damage. The adults are about 
one-eighth inch long, with three teeth, one very prominent and two 
smaller, on each side of the concave elytral declivity. They excavate 
an irregular central nuptial chamber, with three or four short curved 
or S-shaped galleries radiating therefrom. Four eggs are laid in 
each egg pocket and the four laval mines issuing from each pocket are 
a characteristic feature of its work. (See p. 111 for a general discus- 
sion of the work and habits of the /ps beetles. ) 
Other species of 7ps which attack spruce include the following: 
Species of Ips Host and distribution 
. perturbatus Eichh__ yee _ White spruce. Northern Canada and 
Alaska. 
ater PUnClus Wich Sse ee White spruce and Engelmann spruce. 
a 
I 
Alaska, Yukon, and British Columbia. 
T_interrupris, Manns» 252) 32s Sitka spruce, white spruce. Oregon to 
I 
Alaska and eastward. 
SOLOS. SS Was Oe Pee Be Engelmann spruce. British Columbia 
and Rocky Mountain region. 
LE inidens Mann) 2 oa a ee Engelmann spruce, Sitka spruce, and 
probably white spruce. Canadian 
Rockies and British Columbia. 
I. engelmanni Sw__------------------. Engelmann spruce and white spruce in 
Same region. 
TT. YOoheensis “SW a __.. Engelmann spruce and probably white 
spruce. British Columbia. 
The Sitka spruce hylesinus (Pseudohylesinus sitchensis Sw.) is a 
small, densely scaly, suboval bark beetle which is found attacking 
felled or dying Sitka spruce in British Columbia, Washington, and 
Oregon. 
Scierus annectens Lec., a small reddish-brown bark beetle about 
one-eighth inch long, attacks white spruce, Engelmann spruce, lodge- 
pole pine, and probably Sitka spruce in western Canada and the 
Northwestern States. 
Dryocoetes affaber Mann. attacks the tops of felled and dying 
Sitka spruce, Engelmann spruce, and Douglas fir from Alaska south- 
ward into the Northwestern States. The adults, which are less than 
one-eighth inch in length, construct irregular, short egg galleries. 
Dryocoetes confusus Sw. (p. 125) may also be found attacking and 
sometimes killing Engelmann and other spruces. 
HEMLOGK BARK BEETLES 
While hemlocks have a number of bark-beetle enemies, these are 
mostly of secondary importance, and seldom are any large number 
of trees killed. 
Western hemlocks (Tsuga heterophylla) are sometimes attacked 
and killed by the Douglas fir beetle (p. 120) when associated with 
Douglas fir. At times weakened trees are attacked by species of 
Scolytus and Pseudohylesinus. 
Mountain hemlocks, when in mixture with lodgepole pine, are 
sometimes killed by the mountain pine beetle (p. 102), but are most 
frequently attacked by a species of Scolytus. 
