A redescription ofAcruliopsis tumidula (Mäklin, 1853) comb. n., with new data onA. ussuriensis Zerche, 2003 (Coleoptera: Staphylinidae: Omaliinae)

Acruliopsis tumidula (Mäklin 1853) comb. n. = ( Omalium tumidulum Mäklin 1853) is redescribed and illustrated; a lectotype for the species is designated. New distributional data for A. ussuriensis Zerche, 2003 are reported; its male abdominal structures as well as female accessory sclerites are visualised for the first time. A modified key for identification of all the known species of the genus is provided.