Taxonomy of the Genus Eusphalerum Kraatz (Coleoptera: Staphylinidae: Omaliinae) from South Korea

The eusphalerine single genus, Eusphalerum Kraatz contains about 230 species distributed in the Holearctic and Oriental regions. In East Asia, 74 species of the genus are studied and Zanetti reported six species from North Korea in 1993. They are known to feed pollen on flowers of shrubs and trees. As a result, they have peculiar molar structure. Members of the Eusphalerum are characterized by the combination of following features: body spindle‐shape and parallel‐side; eyes large and protruded, temple short; mandibles subtriangular and edentate, molar and scissorial area fused, medial surface of molar with grinding cones; maxillary palpomere 4 as wide as palpomere 3; antennae gradually wide apically, antennomere 10 almost as wide as long; tarsomeres 1–4 short and broad, ventral surface setose densely, tarsomere 5 as long as or longer than basal four combined. In this paper, we report four South Korean Eusphalerum species and provide illustrations of the diagnostic characters including first line drawings of spermatheca and accessary sclerite. The specimens studied are deposited in the Chungnam National University Insect Collection (CNUIC), Daejeon, Korea.