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

Logo: What Bug Is That? Logo: Taxonomy Research & Information Network



Most adult elmids and all larvae live under water, usually in lotic habitats with rocky bottoms, clear water and higher oxygen content, and feed on decaying vegetation or algae. Larvae breathe through the anal gills, but they possess functional spiracles in the last instar, when they leave the water to pupate.

Most adults are capable of remaining under water for long periods by maintaining an air bubble.


Small to minute, darkly pigmented beetles, with moderately short, slender or slightly incrassate antennae, moderately to widely separated coxae, and long legs with simple tarsi and long claws. Larvae onisciform to cylindrical, with movable operculum and paired hooks on S9 and 3 pairs of retractile anal gills. Adult Elminae  are glabrous or sparsely pubescent above but have ventral tomentose tracts which serve as a plastron; adult Larainae are densely pubescent but lack a ventral plastron.


Australian Larainae include Hydora , Ovolara , Stetholus and Potamophilinus , while the Elminae are placed in several genera, the largest of which are the endemic Simsonia , Notriolus and Kingolus , and Austrolimnius , which also occurs in South America. Larvae of several Australian elmids have been reared but not yet described (Glaister 1985). [Brown 1981, 1987; Hinton 1965, 1968; Stride 1955.]

  • Stetholus sp.