. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. THE GENUS DENDROCTONUS. 107 mines extend at right angles from the main galleries and are exposed in the inner bark, often marking the surface of the wood (figs. 66, 67, 68). The stout, whitish, grublike larvae transform to pupae and adults in cells, either exposed or not, in the inner bark. The broods usually work independently of the other species, and often occupy and separate the bark on the lower to middle trunks of standing and felled trees. The fresh attack on living or freshly felled trees is indicated by
. Bulletin. Insects; Insect pests; Entomology; Insects; Insect pests; Entomology. THE GENUS DENDROCTONUS. 107 mines extend at right angles from the main galleries and are exposed in the inner bark, often marking the surface of the wood (figs. 66, 67, 68). The stout, whitish, grublike larvae transform to pupae and adults in cells, either exposed or not, in the inner bark. The broods usually work independently of the other species, and often occupy and separate the bark on the lower to middle trunks of standing and felled trees. The fresh attack on living or freshly felled trees is indicated by red borings at the entrance to the galleries and lodged in the loose bark on the trunk or around the base; the leaves of the dying trees fade, turn pink- ish yellow, or remain green in the fall succeeding spring and summer attack, but turn brown during the winter and spring. SEASONAL HISTORY. OVERWINTERING STAGES. The winter is passed in the inner bark of trees, logs, etc., attacked the preceding spring and summer, principally as developed broods of adults, but also as young to matured larvae and probably parent adults. ACTIVITY OF OVERWINTERED BROODS. Activity begins during the first warm weather in April, when the parent adults ex- tend their galleries and de- posit eggs. The young adults of the developed broods be- gin to emerge by the middle of April, and continue to come out during June or July or later. The overwintered, large larvae evidently complete their development and emerge by the first of August, while the broods of young larvae of the possible second generation from eggs deposited in the fall evidently complete their development and begin to emerge in August, and continue to do so until cold weather, when some will begin their second hibernation as fully developed broods of Fig. 65.—The Douglas fir beetle (Dendroctonus pseudo- tsugae): Adult. Greatly enlarged. (Author's illustra- tion.). Please note that these images are extracted from scanned page ima
Size: 1254px × 1994px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubje, booksubjectentomology
