The alder bark beetle, Alniphagus aspericollis (LeConte),is bivoltine on Burnaby Mountain, B.C. The principal spring attack occurredin May and the second generation attack from mid July to early August.Mature adults overwinter in shallow galleries underneath the bark whilelarvae, pupae, and callow adults overwinter in the brood galleries. Sporadicemergence occurred in warm periods throughout the winter but the first egggalleries were not observed until early March. Windfalls and standing treeswere attacked.Adult sexes can be distinguished by the fused (female) orseparate (male) seventh and eighth abdominal tergites. Females attack thehost first and are soon joined by the males. Single egg galleries extendingabout 8 cm parallel to the length of the bole are most common. Eggs are laidon both sides of the gallery; the larvae mine outward at right angles to theegg gallery and then usually up or down the bole. Adult gallery constructionand oviposition and larval mining habits were observed throughplexiglass–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.