Orthotomicus caelatus (Eichh.) occurs throughout eastern 
United States and eastern Canada. It commonly breeds in thick 
bark on stumps and logs or at the bases of weakened or dying 
pines, spruce, larch, and balsam fir. The adult is dark reddish- 
brown to nearly black and from 2 to 2.3 mm. long. Short, radiat- 
ing egg galleries originate at central nuptial chambers, and from 
one to six eggs are laid in large niches or pockets along their 
sides. Specimens of a morphologically closely related species, 
possibly a biological variety, have been collected from the twigs 
of fire-killed young loblolly pines in North Carolina, where they 
were apparently breeding as well as mining out the pith and 
wood. Adults were also reared from dry twigs and the tips of 
longleaf pine logging slash (41). The western species, O. vicinus 
LeC., breeds in black spruce in the Lake States. 
The genus Pityokteines Fuchs is represented in the United 
States by several species, only one of which occurs in eastern 
forests. The beetles breed primarily in dying or felled trees, par- 
ticularly firs and spruces. The eastern species, P. sparsus (LeC.), 
is frequently injurious to balsam fir, killing large groups of trees. 
Pines, spruce, and larch are also attacked. Infestations are found 
in slash, in the limbs and tops of trees dying suddenly, in wind- 
throws, and in weakened and perfectly healthy trees. The adult 
is about 2 to 3 mm. long and is distinguished by long, yellow hairs 
arising from the front of the head and from the apical margin of 
the pronotum. Eggs are deposited in large niches along the sides 
of several galleries which radiate away from a central nuptial 
chamber and scar the wood deeply. Larval tunnels are longitud- 
inal and follow the grain of the wood. 
The genus Dryocoetes Eichh. is represented in North America 
by seven species, five of which occur in eastern forests (99). They 
usually breed in the upper portions of trunks, in the roots of 
injured or dying trees, or in windfalls. Both coniferous and 
deciduous trees are attacked. 
Dryocoetes affaber (Mann.), the most common North American 
species, occurs throughout the spruce forests of the continent 
north of North Carolina and New Mexico. Spruces are preferred 
hosts, but pines and larch are also attacked. Infestations occur in 
felled trees, stumps, and the trunks of standing trees. The female 
adult is reddish-brown to black, has the frons pubescent, and is 
from 2.5 to 3.3 mm. long. 
Dryocoetes autographus (Ratz.) is widely distributed in the 
coniferous forests of North America. Infestations are usually 
found at the base and in the roots of dying or injured standing 
trees, or in stumps or felled trees. A wide variety of trees are 
attacked including spruce, hemlock, Fraser fir and pines. There 
have also been reports of infestations in yellow poplar. The adult 
is from 3.5 to 5 mm. long. It differs from the adults of all other 
species in the genus in having a distinctly punctured pronotal 
disk, a convex declivity with the sutural interspace only slightly 
raised, and in the absence of a dense mat of hair on the female 
frons. 
The birch bark beetle, Dryocoetes betulae Hopk., occurs from 
coast to coast in Canada and south to Florida and Mississippi in 
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