. Forest insect conditions in British Columbia [microform] : a preliminary survey. Insect pests; Arbres; Forest insects; Insectes nuisibles; Insectes forestiers; Trees. 13 The Western Pine Bark-beetle. {Dendroctonus brevicomia Lee.) This is one of the two injurious species concerned. It is a cylindric, hard- shelled beetle, from two to three-sixteenths of an inch in length, and varies in colour from light-brown, when recently transformed, to nearly black whea mature. It is clothed above with very short inconspicuous hairs. The younfe are small, whitish, footless grubs, with powerful jaws, foun
. Forest insect conditions in British Columbia [microform] : a preliminary survey. Insect pests; Arbres; Forest insects; Insectes nuisibles; Insectes forestiers; Trees. 13 The Western Pine Bark-beetle. {Dendroctonus brevicomia Lee.) This is one of the two injurious species concerned. It is a cylindric, hard- shelled beetle, from two to three-sixteenths of an inch in length, and varies in colour from light-brown, when recently transformed, to nearly black whea mature. It is clothed above with very short inconspicuous hairs. The younfe are small, whitish, footless grubs, with powerful jaws, found boring chiefly in the out< portion of the inner Vie- 2.— Tlio Western Pine oHark-bctlp. (DendroclonuK hriricomin hoc.) Gn'atly enlarncd. (Original.) The Libe-histohy .\nd Habits,—The beetles enter the green bark of healthy, injured, or recently felled trees in pairs during the summer months, and excavate long, irregularly winding egg-tunnels, mostly upwards from the entrance-hole, through the inner bark, upon the wood-surfucr. A portion of tiie red boring-dust and excrement is thrust from the entranco-hole and lodges in tiie bark crevices below; the remainder blocks the egg-tunnels. When the attack is made upon green trees, the exuding resin forms in irregular masses about the entrance-hole, and drops fall and adhere to the bark below. The male beetle keeps the entrance free through this mass of gum, which is known as the "pitch-tube" or "; The presence of these gum-tubes upon tlic bark of injured trees indicates positively that the tree was attacked while the_bark was green and full of fluid resin. 57425—3^. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Swaine, J. M. (James Malcolm), 1878-1955; Canada. Division of Entomology; Dominion Experimental Farms and S
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