. Eastern forest insects . Several species of Xylotrechus Chev. occur in eastern forests. Adults are characterized by their moderate size, their short, fili- form antennae, and a F-shaped callosity on the front of the head. Xylotrechus quadrimaculatus (Hald.), the birch and beech girdler, breeds in the branches of birch, beech, blue beech, maple, and alder in the Eastern States. Adults are about 12 mm. long. The thorax is black with four yellow spots; the wing covers pale brown with faint white marks. Eggs are deposited in the axils of twigs, in bark crevices, and in healed over injuries on br
. Eastern forest insects . Several species of Xylotrechus Chev. occur in eastern forests. Adults are characterized by their moderate size, their short, fili- form antennae, and a F-shaped callosity on the front of the head. Xylotrechus quadrimaculatus (Hald.), the birch and beech girdler, breeds in the branches of birch, beech, blue beech, maple, and alder in the Eastern States. Adults are about 12 mm. long. The thorax is black with four yellow spots; the wing covers pale brown with faint white marks. Eggs are deposited in the axils of twigs, in bark crevices, and in healed over injuries on branches. Young larvae feed beneath the bark, often girdling and killing the branch quickly. Later they bore toward the pith in concentric circles until the branch is almost severed. At this point, they turn and bore toward the tip, packing their tunnels with granular frass. Before reaching the tip they construct pupal cells in which they spend the winter and in which they pupate in the spring. Damaged branches up to 2 inches in diameter frequently fall to the ground, with the larvae in them, during mid-summer. There is one generation per year. The gall-making maple borer, Xylotrechus aceris Fisher, breeds in the trunks and branches of various maples, causing the forma- tion of galls. The adults resemble those of the birch and beech girdler, although they are somewhat smaller and have fainter spots on the thorax and stronger markings on the elytra. Eggs are deposited during mid-summer in wounds or at the bases of small dead twigs along the trunk. The larvae bore directly into the sapwood. Later they construct tunnels in the heartwood, often completely destroying the center of the trees and causing the formation of galls or swellings about the wounds. During the second summer of their lives, they bore either directly upward or downward and pupate in cells at the end of their tunnels. Infested trees are never killed outright but are seriously weakened, be- coming subject to breakag
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectforestinsects
