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horned passalus beetle

horned passalus beetle (Odontotaenius disjunctus)

Features and Behaviors

The horned passalus beetle is also known as a Bess beetle, Bess bug, Betsy beetle, patent leather beetle or peg beetle. It ranges in size from about an inch and one-fourth to an inch and one-half. Its body is elongated, and the elytra (hard wing covers) have distinct striations. Larvae have two pairs of normal legs and one pair (the hind one) that are shorter.

The species can be found throughout the year in rotting logs where it lives in small colonies. It feeds on rotting wood and fungi. The larvae are cared for by adults of both sexes. The larvae eat rotting wood pre-chewed by adults and may eat the feces of adults as well. Adults are sometimes found at lights. Both adults and larvae make sounds by rubbing body parts together, serving as a means of communication between them.

Illinois Range


​Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Coleoptera 

Family: Passalidae

Illinois Status: common, native