332 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
gressive species often attacking the leaf-bearing part of the hving 
twigs of several species of pine, much after the manner of J/yeloborus. 
The egg galleries are in the pith, and the twigs are killed and the wood 
riddled by the larval burrows. It is known from Quebec and Maine 
to Georgia and westward to Texas and Wisconsin. Known hosts 
include longleaf, shortleaf, loblolly, white, pitch, Virginia, and slash 
pines, and deodar cedar. Cutting and burning the wilted twigs will 
destroy the brood. 
Pityophthorus cognatus Blkm. is one of the largest of the eastern 
species, being stout and more than 2.5 mm. long. “Tt has been taken 
from white, red, and Virginia pines in North Carolina. P. cariniceps 
is similar in size and proportions to P. cognatus and is widely dis- 
tributed and common in eastern Canada and in the northern tier of 
States from Maine to Minnesota. It commonly breeds in the smaller 
branches of white and red pines. It has also been taken from balsam 
fir. P. dentifrons Blkm., about 2.2 mm. long and moderately stout, 
breeds in red spruce in Maine, New York, West Virginia, and North 
Carolina. 
A number of small, slender, closely related species are found in the 
twigs of pine, spruce, and fir. They are all about 2 mm. long and 
nearly exactly three times as long as wide. While they are very simi- 
lar in structure the several species can be separated by the character 
of the front of the head of the females. Some of them are found in 
twigs, which appear to have been healthy when attacked, but are found 
principally on lower limbs, and are not numerous enough to cause 
much injury. Pityophthorus patchi Blkm. breeds in the twigs of 
pine, spruce, and fir in Maine. P. awgustus Blkm. is known from red 
spruce and balsam fir in northern New York. P. briscoei Blkm. 
breeds in the twigs of red spruce in Maine. P. biovalis Blkm. is found 
in Maine and New York in red spruce twigs. P. concavus Blkm. 
has been taken in New York and Michigan in ‘twigs of red spruce and 
red pine. P. mundus Blkm. breeds in ted spruce in New York, New 
Hampshire, and Minnesota. P. balsameus Blkm. is known from 
Maine and West Virginia in balsam fir, red spruce, and red pine. 
The following four species are somewhat similar in general struc- 
ture. They are 2 mm. or less in length, are slightly stouter than the 
group of species just discussed, and are found either in twigs or small 
to medium-sized limbs of conifers. Pityophthorus cascoensis has been 
taken only from red spruce in Maine. P. shepardi is known from 
white spruce in northern Maine and from red spruce in northern New 
York. P. tonsus has been taken from spruce and red pine in New 
Hampshire and Michigan. P. pulchellus ranges in distribution from 
Maine to Wisconsin and southward to North Carolina and Texas. 
The known hosts include Virginia, pitch, jack, and red pines, red 
spruce, and balsam fir. 
All the remaining species of Pityophthorus to be mentioned agree 
in having the apex ‘of the elytra drawn out into a more or less sharp 
point. The species range in size from 1.3 to 2.7 mm. long. Some of 
the species attack limbs or stems several inches in diameter, while 
others are found in small limbs or twigs. P. pullus is a very com- 
mon species, but is seldom injurious. It ranges from 1.8 to 2.7 
mm. in length and is shghtly more than three times as long as wide. 
It is often found in material several inches in diameter. It occurs 
