The
rain beetles are a group of
beetles found in the far west of
North America. They spend most of their lives underground, emerging in response to rain or snow, thus the common name. Formerly classified in the
Geotrupidae, they are currently assigned to their own family
Pleocomidae, considered the
sister group to all the remaining families of
Scarabaeoidea. The family contains a single
extant genus,
Pleocoma, and one
extinct genus,
Cretocoma, described in 2002 from
Late Cretaceous deposits in
Mongolia.