INSECT ENEMIES OF EASTERN FORESTS 333 
from Massachusetts to Michigan and southward to South Carolina and 
Texas. White, longleaf, shortleaf, loblolly, pitch, and Virginia pines 
are known hosts. 
Pityophthorus bellus Blkm. is somewhat similar in size and general 
appearance to the foregoing, but the female has the front of the head 
flattened and ornamented with long hairs. Its distribution ranges 
from West Virginia to Florida and westward to Texas. Several species 
of pine are known hosts. P. consimilis is a small reddish-brown 
species, 1.6 mm. long. It breeds both in twigs and small branches and is 
often found in the lower, suppressed branches of pine. It is common 
and widely distributed, occurring from Nova Scotia to Manitoba in 
Canada, and in the United States from Maine to Wisconsin and south- 
ward to Georgia and Mississippi. Known hosts include white, jack, 
red, pitch, Virginia, shortleaf, loblolly, longleaf, and slash pines, red 
spruce, and balsam fir. P. nudus is very similar to P. consimilis in 
structure, habits, distribution, and hosts, but isnot socommon. P. an- 
nectens Lec. varies considerably in size but averages about 1.5 mm. 
long, and three times as long as wide. Its distribution ranges from 
West Virginia to Florida and westward to Texas. The hosts are 
Virginia, pitch, loblolly, shortleaf, longleaf, and slash pines. 
Bark Beetles of the Stem and Larger Limbs 
Several genera of the subfamily Ipinae are often found breeding in 
the trunks and large branches of trees of sapling, pole, and larger 
sizes. Some species may also breed in smaller branches, but they are 
more often characteristic of larger material. Nearly all the forms here 
discussed choose conifers as their host, but one eastern species of 
Dryocoetes is found in broad-leaved trees. Species of Pityogenes and 
a few species of Pityophthorus, already discussed under twig beetles, 
may also be found in medium-sized limbs and stems. 
Most of the forms here discussed prefer to breed in cut or broken 
trunks or branches of medium size, but a few will attack growing trees, 
and if numerous enough, will kill them. However, none of the species 
are able to continue depr edations on healthy trees, because in attacks 
on vigorous bark their numbers are depleted with each generation. 
The burrows made by the species here discussed are all of the radiate 
type, but those of most species have distinguishing characteristics hav- 
ing to do with the host, the diameter, ee and direction of the egg 
valleries, and the manner of placing the eggs 
The genus /ps contains bark beetles ranging in size from 2.6 to 6.5 
mm. in ‘length, and in color from reddish-brown to black. The rear 
end of the body i is diagonally truncate and concave, with the margins 
at each side ornamented with three to six teeth, variously developed 
and differently arranged for each species. The ‘posterior end of this 
concavity ends in a shelf distinct from the margin of the elytra. 
Most of the species breed by preference in pine slash or in recently 
cut or broken trees, and attack living trees only when immense num- 
bers have bred up in slash and upon emergence do not find suitable 
material in which to breed. In living trees, beetle mortality is so 
great that unless the young trees have been weakened by drought, 
fire injury, or other causes, the infestation continues for only one or 
two generations of the beetles; however, if the young stand is decadent 
