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

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A small family, with some 16 species in seven genera in Australia, many of them probably introduced along with domestic cattle. One ( Australosepsis frontalis (Walk.)) is mainly associated with the water buffalo. Almost all have distributions extending into other regions, some as far as Africa.

Larvae of most species live in animal faeces and adults often swarm nearby. Parapalaeosepsis plebia (Meijere) also swarms around rotting fruit and compost.


Adults are small and ant-like with the habit of continuously waving their wings while at rest. Several species have mixed populations of two forms of male: a larger, red or yellow one and a smaller black one. The significance of this remains unknown. In adults the palps are vestigial and the posterior spiracle has a characteristic fringe of several fine bristles on the lower margin.


One species ( Lasionemapoda hirsuta (Meijere)) is commonest in south-eastern areas and probably endemic, but has spread to Lord Howe and Norfolk Islands and New Zealand. The five species of Parapalaeosepsis occur elsewhere only in the Moluccas, New Guinea and Melanesia - four in rainforest, but P. plebia mainly in cooler areas. The remainder are largely tropical or subtropical, although Australosepsis niveipennis occurs throughout the continent (except Tasmania). They are also widespread throughout the Oriental Region and two species extend to Africa.

  • Sepsidae

  • Sepsidae

  • Sepsidae

  • Sepsidae on fresh dung

  • Sepsidae