Canada. The adult (fig. 70) is light to dark brown and about 14 
mm. long. Each elytron is marked with an irregular line of fine 
yellow hairs back of the base and three transverse bands of gray 
hairs—one band just behind the yellow line at the base, one back 
of the middle, and one at the apex. The larvae feed almost ex- 
clusively in the bark without scarring the wood (279). Recently 
killed trees are preferred. 
Xylotrechus annosus (Say) and X. undulatus (Say) both occur 
in eastern United States. X. annosus, a western species, breeds in 
poplar in the Lake States; X. wndulatus breeds in recently cut 
copes fir, larch, hemlock, and spruce in the northern tier of 
tates. 
The genus Monochamus Serville is represented by several im- 
portant wood-boring species in eastern forests, all of which breed 
in various conifers. The larvae are commonly known as ‘sawyers’ 
because of the loud noise they make while feeding. Freshly cut, 
felled, dying or recently dead trees are preferred. Young larvae 
feed on the inner bark, cambium, and outer sapwood, forming 
shallow excavations called surface galleries and filling them with 
coarse fibrous borings and frass. As they grow older, they bore 
deep into the heartwood, and then turn around and bore back 
toward the surface, thereby forming a characteristic U-shaped 
tunnel. A pupal cell is formed at the outer end of the tunnel, from 
which the adult emerges by chewing a hole out through the re- 
maining wood and bark. Full-grown larvae are often more than 
50 mm. long. Members of this genus often cause heavy losses in 
windthrown or fire-killed timber, in sawlogs left too long in the 
woods before milling, and in improperly handled pulpwood. Hop- 
ping (378) published a key to the adult of the genus. 
The southern pine sawyer, Monochamus titillator (F.), occurs 
throughout the Eastern and Southern States and breeds in 
recently-cut, windthrown, fire-killed, insect-killed, and dying 
pines. The adult is mottled gray and brown and from 18 to 30 
mm. long (fig. 71). Male antennae are often 2 to 8 times as long 
as the body; there is a strong spine on each side of the thorax; 
and the elytral sutures are prolonged into sharp spines. Full- 
grown larvae are up to 60 mm. long. 
In the Piedmont area of the South, adult emergence reaches a 
peak in April and May. However, adult activity continues until 
late fall and probably to some extent throughout the winter. 
Larval habits are as described above for the genus. There are at 
least two generations per year in the South, with overlapping 
broods (750). Prompt salvage and utilization of windthrown and 
dead and dying trees, debarking recently dead trees, and water 
storage of logs will prevent attacks by this species. 
The white-spotted sawyer, Monochamus scutellatus (Say), oc- 
eurs from Newfoundland to North Carolina, Minnesota, and 
Alaska. White pine appears to be its favorite host but it also at- 
tacks many other conifers such as red and jack pines, balsam fir, 
white, black, and red spruces, and larch. The adult (fig. 72) is 
about 18 to 25 mm. long. The male is completely shiny black ex- 
cept for a small rounded white spot at the base of the elytra; 
females are of the same color or have the elytra mottled with 
white spots. 
203 
