Adults bore directly into the wood and their main galleries 
may have several branches (fig. 100). Larval cradles are extended 
both upward and downward from these galleries, and run parallel 
to the grain of the wood. Pines killed by Ips bark beetles in the 
South are often attacked by the species. The western species, 
G. aciculatus Blkm., has been observed attacking ponderosa pine 
in South Dakota. 
COURTESY OF DUKE UNIV. SCH. OF FOREST. 
FIGURE 100.—Tunnels of the am- 
brosia beetle, Gnathotrichus ma- 
teriarius, in the wood of a short- 
leaf pine. 
Ambrosiodmus lecontei Hopk. has been recorded from Florida 
and North Carolina and has been collected from Asiatic Chestnut, 
red maple, and walnut (41). The male adult is yellowish-brown 
and 1.7 mm. long. The entrance galleries run straight into the 
wood for a short distance and the egg galleries branch perpen- 
dicularly and run generally parallel to the grain of the wood. 
A. linderae Hopk. and A. tachygraphus (Zimm.) have been re- 
corded from several eastern and southern States. A. linderae has 
been collected from Asiatic Chestnut; A. tachygraphus from 
yellow poplar, sugar maple, boxelder, beech, and birch. 
Ansandrus pyri (Peck), the pear blight beetle, is widely dis- 
tributed in southern Canada and the United States. It attacks all 
of the common fruit trees as well as a great many other deciduous 
trees. In North Carolina, it has been collected from yellow poplar, 
chestnut, holly, honey locust, and hackberry (41). Dead, dying, or 
weakened trees are preferred, but apparently healthy trees may 
also be attacked. Female adults are black with yellow appendages 
and are about 3 mm. long. 
The genus Xyleborus Eichhoff is represented by 17 species in 
the United States and Canada, 16 of which occur in eastern 
United States. All species are ambrosia beetles. Many breed in 
both coniferous and deciduous trees and shrubs of all sizes. 
Dying, unhealthy, felled, or weakened trees or wounds and dead 
areas in living trees are preferred for attack. Distinguishing 
characteristics of the adults are: a five-segmented antennal funicle 
with the fifth joint short and broad; the outer face of the antennal 
club obliquely truncate; and the eyes emarginate. The pronotum 
is longer than broad and without serrations on the anterior mar- 
gin. Beal and Massey (41) published keys to many of the species 
commonly found in the eastern United States. Bright (100) pub- 
lished keys to all species occurring in the United States and 
Canada. 
Xyleborus saxesenst (Ratz.) occurs commonly throughout 
southern Canada and the United States and breeds in a wide 
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