usually preferred, but a few species confine their attacks to de- 
ciduous trees. Attacks are usually confined to broken, cut, deca- 
dent, or dying material, but perfectly healthy material may be 
attacked. The adults are quite small, mostly from 1.3 to 1.75 mm. 
long, and range in color from light brown to black. Females are 
distinguished by the presence of long, yellowish hairs on the 
front of the head (69, 70, 71, 698). A few common species of 
Pityophthorus Eichh. are discussed here. 
Pityophthorus natalis Blackman breeds in redbud from Mary- 
land and West Virginia to Mississippi. The adult is reddish- 
brown and about 1.5 mm. long. P. liquidambarus Blackman 
breeds in sweetgum, probably wherever it grows. The adult is 
reddish-brown and 1.8 mm. long. P. rhois Swaine, P. crinalis 
Blackman, and P. scriptor Blackman breed in sumac. 
Pityophthorus pulicarius (Zimm.) occurs throughout eastern 
United States and in eastern Canada. It attacks all species of 
pines in its range and has also been recorded from deodar cedar. 
Infestations occur in the wood and pith of twigs of dead and 
dying trees, in small trees killed by fire, in slash, and in one-year 
old cones of felled pines. Scions of grafted slash pines being pre- 
pared for seed orchard establishment in Florida have been seri- 
ously injured. The adult is reddish-brown and 1.8 to 2.0 mm. long. 
Additional eastern species of Pityophthorus and their hosts are 
as follows: P. opaculus LeC.—white pine, larch, balsam fir, and 
various spruces from Maine to West Virginia and South Dakota; 
P. patchti Blackman—red spruce and balsam fir in New York; 
P. biovalis Blackman—red spruce and red pine in New York and 
Michigan; P. balsameus Blackman—balsam fir, red spruce, and 
red pine in Maine and West Virginia; P. dentifrons Blackman— 
red spruce from Maine to North Carolina; P. cariniceps LeC.— 
white and red pines in the northern tier of states and southern 
Canada; P. annectens LeC.—living trees and slash of various 
pines from West Virginia to Florida and Texas; P. shepardi 
Blackman—white and red spruce in Maine and New York; P. - 
pulchellus Eichh.—probably all species of pines from Maine to 
North Carolina and Texas; also red spruce and balsam fir; and 
P. puberlus (LeC.)—all species of conifers from southern Can- 
ada to North Carolina and westward to the Lake States and 
Kansas. 
The genus Pseudopityophthorus Swaine is closely allied to the 
genus Pityophthorus. It differs in that the adults have a longer 
and more acute prosternal process. The first segment of the an- 
tennal club also is longer than those in Pityophthorus, and the 
males rather than the females have long, yellowish hairs on the 
front of the head. The majority of species prefer to breed in the 
inner bark of recently cut or dying limbs of various species of 
oaks. A few species attack other tree species, and some attack 
and kill perfectly healthy limbs. The genus was revised by 
Blackman (72). 
Pesudopityophthorus minutissimum (Zimm.), the oak bark 
beetle, a common and widely distributed species from Quebec and 
Massachusetts to Georgia and westward to Mississippi and Color- 
ado, breeds in various species of oaks and occasionally in many 
other hardwoods. The adult is dark reddish-brown and from 1.5 
to 1.9 mm. long. In the southern portions of its range, it is active 
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