INSECT ENEMIES OF EASTERN FORESTS old 
elm infected with the Dutch elm disease. This suggests the possibility 
of its acting as a disease vector, as its habits are well adapted to such 
arole. Up to the present, however, it has not been found in sufficient 
abundance to cause great alarm. 
Scolytus fagi Walsh, the beech bark beetle, is somewhat similar to 
S. sulcatus, but is larger, 4.5 to 5 mm. long, and the elytra have the 
striae distinctly impressed, and the strial punctures are much coarser 
than those of the interspaces. The recorded hosts are beech and hack- 
berry, and this beetle occurs in the Mississippi Valley from Illinois 
to Texas. Very little is known of its habits, and its economic im- 
portance is doubtful. 
Scolytus piceae, the spruce scolytus, is readily distinguished from 
other eastern species by the presence of a tubercle or spine extend- 
ing backward from the center of the second ventral abdominal 
segment, and distinguished from S. mu/tistriatus in having the elytra 
subtruncate. It occurs from Quebec and Maine westward to Colorado, 
Montana, and Manitoba. It seems to be confined to the northern for- 
ests and is known to breed in white spruce, red spruce, Englemann 
spruce, eastern larch, and eastern balsam fir. Its burrows differ from 
those of other eastern forms in consisting typically of two, or some- 
times three, ege galleries extending longitudinally from a central 
nuptial chamber. It breeds by preference in broken limbs or tops of 
its host trees and is not notably injurious. 
Three species of small beetles of the genus Crypturgus Erichson are 
often common in the Eastern States. They are very small brown or 
black beetles, about 1 mm. long, and are found in the inner bark of 
dying or dead coniferous trees. Their burrows usually originate from 
the burrows of larger bark beetles, such as those of species of Dendvoc- 
tonus Polygraphus, and Ips, but sometimes the so-called ventilation 
openings made by Monochamus spp. are utilized for access to the inner 
bark. Species of Crypturgus are not injurious and are here mentioned 
merely because they often occur in infested material killed by other 
more destructive species and may be found under suspicious circum- 
stances after the real aggressors have left the dead bark. C. atomus 
Lec. occurs from Maine and northern New York to West Virginia and ~ 
westward. (C. corruguatus Sw. is known from Maine, New York, and 
Pennsylvania, and C. alutaceus Sz. from New Jersey to Florida. 
Polygraphus rufipennis, the four-eyed spruce bark beetle, is 
slightly less than 2.5 mm. long and is black with the elytra brownish 
black. It can readily be distinguished from any similar form by the 
fact that the eyes are completely divided and the antennal club is 
unsegmented. The favorite host for this Polygraphus is spruce, and 
all species of the genus Picea are readily infested. Larch is also com- 
monly attacked, but pine is less common as a host. The burrows are 
of the radiate type, with from 2 to 6 egg galleries, each made by a 
separate female. The beetle is not aggressive, and therefore the bur- 
rows are nearly always found in either dying, broken, or recently cut 
material. Occasionally green, standing trees are attacked and killed, 
but it is doubtful that really vigorous trees ever succumb to this beetle. 
Trees left in cutting operations are sometimes killed, but in such 
cases conditions are abnormal, owing to the emergence of myriads of 
the beetles from the slash and the weakening of the residual stand 
by the removal of the merchantable timber. It is therefore very ques- 
