INSECT ENEMIES OF EASTERN FORESTS 589 
This species is the most common of our horntails, infesting apple, 
beech, birch, elm, hickory, maple, oak, pear, and sycamore. It is 
widely distributed and probably occurs throughout most of the range 
of its food plants in North America. The insects attack dead, dying, 
and seriously weakened trees, and injured and dead areas in living 
trees. The larvae bore galleries through the wood, thus weakening 
the supporting strength of trunks and branches, and undoubtedly aid 
in the penetration and distribution of wood-destroying fungi. The 
adults emerge and are active early in the summer. The females ap- 
parently examine the host trees with care before selecting a place to 
bore into the wood for ovipositing. Although eggs are deposited 
singly at a depth of 1% inch in the wood, a number may be found near 
each other in a limited area. The larvae on hatching in the wood make 
galleries and feed for probably one season. Some authors believe that 
there is one generation annually. Transformation takes place in the 
burrow and the adults emerge through circular holes about 1% inch 
in diameter. 
SuBFAMILY SIRICINAE 
Uvrocerus albicornis (¥.), the white-horned horntail, is blue-black 
or black and measures about 1 to 114 inches in length. Most of the 
antennae, the cheeks, the bases of the tibiae and the tarsi, and some- 
times lateral spots on the abdomen are white. The wings are smoky 
brown and expand nearly 2 inches. The horned tail of the female is 
shaped lke the head of a lance. This species occurs throughout 
boreal North America and infests cedar, pine, and spruce. 
The female of Urocerus flavicornis (F.), the yellow-horned horn- 
tail, is about 114 inches in length, and is black, with the first and sixth 
segments and part of the seventh yellow. The male measures about 
4£ inch in length and is black with segments 2 to 5 of the abdomen 
orange-yellow. This species infests spruce and other conifers through- 
out northern New England, northward to Labrador, and westward to 
the Pacific coast. U. cressoni Nort., the black and red horntail, is 
widely distributed over New Errgland and has been found on poplar. 
The blue horntail (Sire juvencus (1.)) is metallic blue, except for 
the legs, which are dark red or marked with yellow. It is found in 
pine, fir, and spruce and has been reported from New England, 
throughout the Western States, and in parts of Canada. S. juvencus 
race cyaneus F. infests spruce and pine in New England. 8S. edwardsii 
Brulle infests badly weakened pitch pine trees in New England. 
Famity CEPHIDAE 
The Stem Sawflies 
The stem sawflies are borers in stems of plants or in the tender shoots 
of trees and shrubs. The adults are slender-bodied and are mostly 
black or dark colored, either with or without narrow yellow bands, 
and are seldom more than 84 inch in length. The antennae are fili- 
form, shghtly spindle-shaped or club-shaped, and with 20 to 30 seg- 
ments. The anterior tibiae each have only one apical spur, which is 
cleft at the apex, the inner tooth is small, and the outer tooth large 
(Yuasa 439). The larva is generally pale or creamy white; the head 
