Wikipedia
Scydmaeninae are a subfamily of small beetles, commonly called ant-like stone beetles or scydmaenines. These beetles occur worldwide, and the subfamily includes some 4,500 species in about 80 genera. Established as a family, they were reduced in status to a subfamily of Staphylinidae in 2009
Many scydmaenine species have a narrowing between head and thorax and thorax and abdomen, resulting in a passing resemblance to ants that inspires their common name. The largest measure just 3 millimeters long, while some very small species only reach half a millimeter in length. Scydmaenids typically live in leaf litter and rotting logs in forests, preferring moist habitats. A number of types are known to feed on oribatid mites, using "hole scraping" and "cutting" techniques to get through the mite's hard shells.
In addition to the two living subfamilies, the prehistoric subfamily Hapsomelinae, known only from fossils, has been placed here.