A revision of Haematodes Laporte and Weiserianum Bernhauer (Coleoptera: Staphylinidae: Staphylininae: Xanthopygina)

The species of poorly known but charismatic genera Haematodes Laporte, 1835 and Weiserianum Bernhauer, 1927 are revised. Weiserianum syn. nov. is considered a junior synonym of Haematodes, with Haematodes kuntzeni (Scheerpeltz, 1936) comb. nov. Weiserianum woltersi Bernhauer, 1927 syn. nov. is treated as a synonym of Haematodes tenuipes Kraatz, 1858. Haematodes myteros sp. nov., is described from Paraguay and Brazil. As the type series of Haematodes bicolor Laporte, 1835 is considered lost, a neotype, selected from the original type locality is designated. We also designate a lectotype for H. tenuipes Kraatz, 1858 to stabilize nomenclature for this species, which is similar to H. myteros. As far as known, Haematodes is restricted to the southern Neotropical region and may be nest parasites within Acromyrmex and Atta ant nests as are species of the related genus Scariphaeus, but no direct observations are yet available. We provide a key to the four known species of Haematodes and illustrate their diagnostic features.