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

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The small water striders or riffle bugs range in size from 1.5 to 10 mm in length with 17 species recorded as occuring in Australia.

All Australian species of this family live on the surface of still or running freshwater or in marine intertidal areas where they feed on small crustaceans and insects. Some veliids may concentrate in schools on running water where the flow of the water will bring potential prey items within reach.

The Veliidae sometimes use an unusual method of locomotion on the waters surface called expansion skating. In addition to the use of their legs, they sometimes exude a substance from their mouthparts which lowers the surface tension of the water. The effect is to propel the bug away from the lowered surface tension, often at greater speeds than be accomplished by ordinary walking. Due to the flexible mouthparts, the bug can direct the substance in almost any direction and control the route it takes.


Three subfamilies and 4 genera are found in Australia. Haloveliinae contains the genera Halovelia (5 spp.) and Xenobates (2 spp.) both of which are concentrated in the northern parts of Australia. Microvelia , the only genus in the subfamily Microveliinae, contains 8 species and 2 subspecies and is distributed throughout eastern and south-eastern Australia. One species, Microvelia howensis , is endemic to Lord Howe Island. Rhagovelia australica , the only member of the subfamily Rhagoveliinae in Australia, has been recorded only from one locality near Cairns in Queensland.

  • Veliidae (Heteroptera)