rows, are rounded behind, and are without furrows or teeth. 
The adult bores into its host near the ground line, then exca- 
vates a tunnel which may encircle the stem one or more times, 
girdling it. Small stems, from 3 to 10 mm. in diameter, are usu- 
ally attacked. Severe mortality of young sugar maples from 1 to 
5 feet tall has occurred in dense, mature stands in Canada. In 
some areas, almost ail of these young trees have been killed. 
Finnegan discussed the biology of the species in Canada (249) ; 
also its method of transfer of fungus spores (247). 
Two species of the genus Monarthum, M. fasciatum (Say) and 
M. mali (Fitch), occur in eastern North America. Adults of M. 
fasciatum are marked with pale yellow bands across the elytra 
and are about 2.5 to 3 mm. long. In this species, mycetangia are 
possessed by the female (461). This species is most common in 
the South. It breeds in most species of hardwoods, and has also 
been observed in pine and hemlock. Adults of M. malt resemble 
those of M. fasciatum except for their slightly smaller size and 
their uniformly brown color. This species breeds in dying, in- 
jured, or recently cut logs and stumps of practically all species of 
hardwoods throughout the Eastern States. Both species are 
highly destructive of green lumber and fresh logs cf gum in the 
Gulf States. 
Xyloterinus politus (Say), a widely distributed species in eas- 
tern North America, breeds in injured, dying, and recently cut 
trees and limbs of a variety of trees such as beech, birch, hard 
and soft maples, hickory, ash, magnolia, black cherry, red spruce, 
pine, and hemlock. The adult is dark brown to black and about 
2.3 to 3.5 mm. long. The pronotum is almost square, rugose in 
front, and has the anterior margin armed with two to four teeth. 
The elytra are reddish-brown and covered with short, yellow 
hairs. The galleries of this species differ from those of other am- 
brosia beetles in that not only do they often fork and branch 
secondarily, but they also possess four rows of larval cradles, two 
above and two below the gallery (492, 493). Lumber cut from 
infested wood may be severely degraded by adult entrance holes 
and by associated stains. 
Five species of the genus Trypodendron Stephens occur in 
eastern America. Adults are distinguished by having divided eyes 
and by the absence of distinct surtures in the antennal club. The 
antennal funicle is four-segmented; the front of the male is 
broadly excavated; the oral region of the head is visible from 
above; and the corneous basal segment of the antennal club is 
strongly angulate in front and produced toward the middle. 
The striped ambrosia beetle, Trypodendron lineatum_ (Oliv.), 
occurs throughout Canada and the Northern States and breeds in 
a wide variety of conifers. It also occurs in the mountains of 
western North Carolina. The adult is brown to black and from 
3 to 3.5 mm. long. The elytra are dark brown to black, and are 
usually marked with lighter colored stripes along the suture. The 
main gallery of the species extends straight into the wood for 1 to 
2 inches and then divides into two or more branches. Larval 
cradles are situated at the upper and lower surfaces of these 
branches. Damage to felled timber, and to damaged, injured, 
dying, or fire-scorched trees is often severe. 
267 
