Diversity of Placusa (Coleoptera : Staphylinidae, Aleocharinae) in Canada,with descriptions of two new species

The Canadian species of the genus Placusa Erichson are reviewed. Eight spec ies are recorded, of which four constitute new Canadian records P. despecta Erichson, P. incompleta Sjoberg, P. petulans Casey, and P. vaga Casey) and two are new to science (P. pseudosuecica Klimaszewski sp.nov., and P. cana densis KIimaszewski sp.nov.). Placusa turbata Casey, one of the two species previously recorded from British Columbia, is here considered a synonym of P. tachyporoides (Waltl) and is reported for the first time from eastern C anada (New Brunswick, Ontario, Quebec). New data are provided on the system atics, distribution, bionomics, and relationships of selected North America n species. A key to the species occurring in Canada is presented with illus trations of the median lobe of the aedeagus, spermatheca, male tergite 8, a ntennae, and outline drawings of the head and adult forebody for each speci es. Selected Palearctic species are also illustrated for easy comparison wi th the closely related Nearctic species. The Canadian distribution is prese nted on contour maps, and world distribution is discussed for all species. The following lectotypes are designated for the Nearctic species which were described from more than one specimen without former holotype designation: Casey (1893, 1911): P. frosti, P. strata, P, tacomae, P. turbata; Erichson (1840): P. despecta; and Sachse (1852): Oxypoda minuta Sachse. Oxypoda min uta is transferred to the genus Placusa and newly synonymized with Tt despe cta Erichson (1840).