Review of Canadian species of the genus Mocyta Mulsant & Rey (Coleoptera, Staphylinidae, Aleocharinae), with the description of a new species and a new synonymy.

Six species of the genus Mocyta Mulsant & Rey are reported from Canada: Mocytaamblystegii (Brundin), Mocytabreviuscula (Mäklin), Mocytadiscreta (Casey), Mocytafungi (Gravenhorst), Mocytaluteola (Erichson), and Mocytasphagnorum Klimaszewski & Webster, sp. n. New provincial and state records include: Mocytabreviuscula - Saskatchewan and Oregon; Mocytadiscreta - Quebec, Ontario and Saskatchewan; Mocytaluteola - New Brunswick, Quebec, Ontario, Massachusetts and Minnesota; and Mocytafungi - Saskatchewan. Mocytasphagnorum is described from eastern Canada from specimens captured in Newfoundland, New Brunswick, Quebec and Ontario. Mocytanegligens Mulsant and Rey, a native European species suspected of occurring in Canada, is excluded from the Nearctic fauna based on comparison of European types with similarly coloured Canadian specimens, which are now identified as Mocytaluteola. The European species, Mocytagilvicollis (Scheerpeltz), is synonymized with another European nominal species, Mocytanegligens, based on examination of type material of the two species. Lectotypes are designated for Eurypronotadiscreta Casey, Athetagilvicollis Scheerpeltz, Homalotaluteola Erichson, Colpodotanegligens Mulsant and Rey, Acrotonaprudens Casey and Dolosotaredundans Casey. The latter species is here synonymized with Mocytaluteola. A review of the six Nearctic species is provided, including keys to species and closely related genera, colour habitus images, images of genitalia, biological information and maps of their distributions in Canada.