What Bug Is That? The guide to Australian insect families.

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Passalids live in rotten logs and exhibit a type of sub social behaviour discussed in detail by Reyes-Castillo and Halffter (1983).


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.


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.]

  • Pharochilus dilatatus

  • Mastochilus australicus