. Eastern forest insects . COURTESY OF DUKE UNIV. SCH. OF FOREST. Figure 99.—Tunnels of the ambrosia beetle, Trypodendron scabricollis, in wood of the lower bole of a loblolly pine. Trypodendron retusum (LeC), the largest of the eastern species, attacks poplars and paper birch throughout the Northern States and southern Canada. It has also been recorded from West Virginia and several Western States. Adults are from to mm. long; the pronotum is broadly emarginate in front; and there is a broad, smoky yellow stripe on each elytron. T. betulae Swaine occurs throughout the Northern States
. Eastern forest insects . COURTESY OF DUKE UNIV. SCH. OF FOREST. Figure 99.—Tunnels of the ambrosia beetle, Trypodendron scabricollis, in wood of the lower bole of a loblolly pine. Trypodendron retusum (LeC), the largest of the eastern species, attacks poplars and paper birch throughout the Northern States and southern Canada. It has also been recorded from West Virginia and several Western States. Adults are from to mm. long; the pronotum is broadly emarginate in front; and there is a broad, smoky yellow stripe on each elytron. T. betulae Swaine occurs throughout the Northern States and eastern Can- ada and breeds in birch. Adults are black and from 3 to mm. long. There is a faint yellow band toward the rear of the pro- notum and a broad yellow stripe on each elytron. T. bivittatum Kirby, the spruce timber beetle, occurs in eastern United States and eastern Canada and breeds in pines, spruces, fir, arborvitae, larch, and hemlock. Its color is similar to that of T. betulae, and it is about 3 mm. long. The genus Gnathotrichus Eichh. contains several species of true ambrosia beetles. The adults are small, cylindrical, and dark brown or black. The head is invisible from above, and the body surface is finely punctured, smooth, and sparsely covered with hairs near the elytral declivity. Blackman (73) revised the genus. Gnathotrichus materiarius (Fitch) occurs from eastern Canada south to Florida and westward to Nebraska and Texas. It breeds in the lower portions of the trunks of dead and dying pines, spruce, balsam fir, larch, arborvitae, and other conifers. Adults are dark brown to black and about to mm. long. The pro- thorax is asperate in front; the disc is much longer than broad; the elytra taper slightly at the rear end, and the declivity is slightly grooved at the suture and covered with short, sparse hairs. 268
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectforestinsects
