INSECT ENEMIES OF EASTERN FORESTS 321 
Species of the genus breed principally in the cupressine branch of 
the pine family, but a few forms are found in pine and in spruce. The 
eastern species infest such native trees as arbovitae, Juniper, and 
cypress, but may also attack allied introduced trees. 
All the species of Phloeosinus are true bark beetles and all are 
monogamous in their breeding habits, constructing rather short, un- 
branched, longitudinal egg galleries between the bark and wood of the 
limbs or trunk of their host tree. The eastern species are not notably 
injurious, because they prefer to attack cut, broken, or decadent bark. 
Occasionally trees that would otherwise continue to live are killed, 
but this is unusual. 
One habit of the insect is moderately injurious to ornamental hedges 
or specimen trees of arborvitae or Juniper. The young adults on 
emerging from their parent hosts feed for a time on the twigs of living 
trees In a manner very similar to that of the species of Scolytus. They 
bore into these small twigs and feed on the sapwood, causing the 
twigs to wilt and break. ‘This injury is seldom serious enough greatly 
to affect the vigor of the trees, but the wilting and hanging twigs are 
unsightly and disconcerting to the owner, and, if sufficiently abundant, 
may affect somewhat the symmetry of the tree. However, the beetles 
never occur in numbers sufficient to cause any considerable damage, 
except in localities where carelessness has been shown by allowing 
breeding material to remain untreated. A prompt burning of all 
limbs and the barking of the trunks of dying or cut cedar or cypress 
will keep down the beetle population to a point where it can do little 
or no damage. ; | 
Of the several species in the eastern half of the country only three 
will be mentioned. All these have the general habits discussed above . 
and for the purposes of this publication differ principally in their 
hosts and distribution. Phloeosinus canadensis, the northern cedar 
bark beetle, breeds principally in the northern white cedar or 
arborvitae. It occurs throughout eastern Canada and the northeast- 
ern part of the United States. P. dentatus, the eastern juniper 
bark beetle, occurs from Massachusetts to Florida and westward to 
Texas. Its principal host is the eastern red cedar, Juniperus virginiana 
L., although other allied trees are also attacked. P. tawodii, the south- 
ern cypress bark beetle, is known only from the Southern States. 
The host is Zaxvodium distichum (L.) Richard. 
Xylechinus americanus, the suppressed spruce bark beetle, 
is dark brown with the legs hghter in color. It is about 2.2 mm. long 
and moderately slender. The eyes have the inner margin nearly 
straight, the antennal funicle is five-jomted, and the club is ovate, 
compact, and very slightly flattened. The pubescence consists of 
ashen sealelike hairs. This species was described from specimens 
found in the bark of white spruce and white pine in Maine and in red 
spruce in the Adirondacks, but it is doubtless more widely distributed. 
A closely related species, as yet undescribed, occurs in the forests of 
the West. The burrows of XY. americanus are of the transverse radiate 
type and were found only in the bark of trees weakened and dying 
from suppression. It is not commonly met with in either of the 
localities in which it was found, and even if numerous would probably 
not be really injurious. No control is indicated as necessary. 
