The other three species of Phloeosinus occurring in eastern North America are: 
P. canadensis Swaine—on eastern redcedar and northern white-cedar in eastern 
Canada and from Maine to the Lake States: P. pini Swaine—on various pines and 
spruces in the Lake States and southern Canada: and P. scopulorum neomexicanus 
Blackman—on juniper and cypress in Texas. 
The genus Chramesus is represented in the East by four species of stout, strongly 
convex, “humpbacked” beetles, less than 2 mm long. They are further dis- 
tinguished by their large, elongate-oval, unsegmented antennal clubs and the five- 
segmented antennal funicle attached to the side of the club. They breed in broken or 
dying twigs and small limbs. The adults construct longitudinal or transverse 
unbranched egg galleries, partly in the bark and partly in the sapwood. C. hicoriae 
attacks various species of hickory throughout the Eastern States and in eastern 
Canada. C. chapuisi LeConte attacks hackberry from Pennsylvania to Florida and 
Texas (/20), and C. subopacus Schaeffer attacks hackberry in the Southern United 
States to Honduras. The fourth species, C. wisteriae Wood, attacks wisteria in 
Mississippi. 
The genus Carphoborus is represented in eastern forests by at least two species. 
The adults are dark brown to black, more or less covered with short scalelike hairs, 
and are less than 2 mm in length. C. bifurcus Eichhoff is a fairly common species in 
the South where it breeds in dying, broken, and cut limbs of pines. 
Polygraphus rufipennis (Kirby), the four-eyed spruce bark beetle, occurs in the 
spruce forests of the United States south in the Eastern States through the Ap- 
palachians. This dull dark-brown beetle, 2 to 3 mm long, can be identified easily by 
its completely divided eyes. Its hosts, in addition to the spruces, are larch, pine, 
and balsam fir. Infestations are usually found in slash and in dead and dying trees. 
However, when heavy populations develop in such material, nearby living trees are 
also subject to attack. The adult is dark brown to black and about 2.3 mm long. 
Eggs are laid in the sides of three to five irregular, short galleries that radiate away 
from a central nuptial chamber. The bark, but not the wood, is slightly engraved. 
Subfamily Scolytinae 
The genus Scolytus is represented in eastern North America by a number of 
species of true bark beetles, several of which are of economic importance (//9). 
Most species feed in twigs or buds of a host species while in the process of seeking 
a weakened host in which they can breed. All species except one breed in deciduous 
trees, and two species have been implicated in the transmission of Dutch elm 
disease. The adults differ from other eastern bark beetles in having the outer angle 
of the foretibia produced into a curved hook and the ventral surface of the abdomen 
ascend abruptly to the rear. In some cases the abdominal declivity is concave and 
ornamented by spines, tubercles, etc. 
The smaller European elm bark beetle, S. mu/tistriatus (Marsham), one of the 
two principal American vectors of the Dutch elm disease fungus, Ceratocystis ulmi 
(Buisman) C. Moreau, was first observed in North America in 1909 at Boston, 
Mass. (202). Since then, it has spread over most of the United States and into 
southern Canada. Its hosts include all species of elm (U/mus) and the related 
Japanese zelkova, Zelkova serrata. Adults are 2 to 3 mm long and distinctly two- 
toned with the elytra red-brown and the other parts black. Males have a bright 
yellow brush on the front of the head. The underside of the posterior is concave and 
armed with a stout spine projecting from the anterior margin of the second 
abdominal sternite (fig. 165A). The larvae are typical legless grubs about 3 mm 
long. 
352 
tet. Os | irae een See. 
