The alder bark beetle, Alniphagus aspericollis (LeConte), is bivoltine on Burnaby Mountain, B.C. The principal spring attack occurred in May and the second generation attack from mid July to early August. Mature adults overwinter in shallow galleries underneath the bark while larvae, pupae, and callow adults overwinter in the brood galleries. Sporadic emergence occurred in warm periods throughout the winter but the first egg galleries were not observed until early March. Windfalls and standing trees were attacked.Adult sexes can be distinguished by the fused (female) or separate (male) seventh and eighth abdominal tergites. Females attack the host first and are soon joined by the males. Single egg galleries extending about 8 cm parallel to the length of the bole are most common. Eggs are laid on both sides of the gallery; the larvae mine outward at right angles to the egg gallery and then usually up or down the bole. Adult gallery construction and oviposition and larval mining habits were observed through plexiglass–bark "sandwiches," and are similar to those in the genus Ips. Pupation occurs in a chamber in the inner bark. Maturation from egg to callow adult required a minimum of 8 weeks.