Wikipedia
Sphaerites
Sphaerites is a genus of beetles, the only genus in the family Sphaeritidae, sometimes called the false clown beetles. It is closely related to the clown beetles but with distinct characteristics. There are four known species, widespread in temperate area but not commonly seen.
Adults range in length from 4.5–7 mm, with oval bodies, black but with a slight bluish-green sheen.
The life histories are poorly known, but they are generally found around decaying matter and fungi. S. glabratus is associated with conifer forests in northern Europe, and seems especially attracted to sap flows from trees, feeding and then mating.