INSECT ENEMIES OF WESTERN FORESTS 137 
often bring about the death of the trees. Trees may harbor succes- 
sive broods of these insects for a number of years before being killed. 
Much damage is caused by the wind breaking off the infested stems 
of young trees within 3 feet of the ground. The winter is passed by 
the very young larvae in the bark, and pupation occurs the following 
July. Damage in plantations can best be reduced by growing trees 
on good sites. 
The poplar borer (Saperda calcarata Say) (42) breeds in felled and 
weakened aspen and poplar throughout most of the United States, 
The adults are elongate, robust, ‘erayish beetles about 1 inch in 
length, with faint yellowish spots on the elytra, and the antennae are 
as long or longer than the 
body. Emergence of the 
adults occurs late in July 
andin August. The female 
chews a slit in the bark, in 
which one or two eggs are 
deposited. The young lar- 
vae mine into the bark and 
remain there over winter. 
They enter the sapwood 
and heartwood the follow- 
ing spring, where they feed 
for 2 years. During this 
time an opening is main- 
tained through the bark 
where the eggs were laid, 
and through this boring 
dust is expelled. When 
mature the larvae construct 
pupal cells near the lower 
end of the larval mines, 
and in these they remain 
inactive until the follow- 
ing spring. In July of the 
third year the adults = 
emerge through the holes  Ficure 68.—Locust borer (Cyllene [oviniae) : A, 
TeeoMovgiuemlanyae torex-: halt “natural size) “(Drawing by ‘Edmouston.) 
pelling frass. 
The amethyst cedar borer, (Hylotrupes) Hemicallidium amethysti- 
num Lec., attacks western red cedar, incense cedar, and juniper; and 
although ‘it usually selects injured or dying trees, it sometimes ap- 
pears responsible for killing healthy trees. The adults are black, 
over 1 inch in length, and have violet or bright-blue wing covers. 
Other species of bark-boring roundheaded ‘beetles are as follows: 
Species Hosts and distribution 
Aime, WorsaluismMuees-. Ha Cypress, juniper, and incense cedar. Western 
States. 
Semanonismioneus, FE. var == Juniper, cedar, big tree, redwood, hemlock, 
spruce, Douglas fir, balsam firs, larch, cy- 
press, and pines. North America. 
Phymatodes tidus Lec 2-2. Cypress, redwood, and cedar. Pacific coast. 
Leptostylus nebulosus Horn__—~-_- Balsam firs. Oregon. 
Phymatodes decussatus Lec_____-. Oak. Washington. 
Acanthocinus obliquus Lee _--_____ Pines and spruce. Western States. 
