Overview
Passalids live in rotten logs and exhibit a type of sub social behaviour discussed in detail by Reyes-Castillo and Halffter (1983).
Description
Shining, black, somewhat flattened beetles, with prognathous head, sometimes horned, characteristically curved antennae, and narrow pedicel or waist between prothorax and elytra. Scutellum not visible; elytra conspicuously striate. Adults stridulate by rubbing a plectrum on each hind wing against a pars stridens on the dorsal surface of the abdomen (Reyes-Castillo and Jarman 1982). Larvae differ from those of other scarabaeoids by being less curved and in having the hind leg reduced to a stump, which produces sound when scraped against a file on the mid coxa.
Distribution
The family is primarily a tropical group, and most Australian species occur in the north. Common Australian genera are
Aulacocyclus
,
Pharochilus
and
Mastachilus
. [Dibb 1938.]