Acknowledgments

The following people must be thanked for their contributions to this key.  Ben Gunn (CSIRO Entomology), for his contribution of taxa and character images.  Gunther Theischinger (NSW Environmental Protection Authority), for the loan of many of the specimens that were used for photography.

General Information

This is a small order of aquatic insects comprising about 2000 species worldwide.  There are 15 recognised families but only four occur in Australia.  Of the 26 Australian genera 24 are endemic and 2 are shared with New Zealand, but at species level all 196 Australian species are endemic.  Stoneflies occur in eastern Australia from Tasmania to Cape York, and in South Australia and southern Western Australia, but not in central or north-western parts of the country.

Adult stoneflies are soft-bodied insects with long antennae, a moderately wide head, three free thoracic segments, and a cylindrical, parallel-sided abdomen terminating in two prominent cerci (and, in males, varied copulatory apparatus).  Typical adult stoneflies have two pairs of membranous wings each with numerous crossveins, the hindwing broader than the fore, but in some species the wings are reduced and in others they are altogether absent.

This key deals only with the larvae, and of all the keys in this series, is the simplest and least demanding.  Identification of larval stoneflies to family level can be based entirely on the configuration of the abdominal gills.  Eustheniidae carry lateral gills on abdominal segments 1-5 or 1-6.  Gripopterygidae carry a tuft of fine gill filaments on the terminal segment.  Austroperlidae carry 3-5 fingerlike gills on the terminal segment, with further fingerlike gills on the cerci or anal plate in some species.  Notonemouridae have no external gills at all.  Additional characters assist in identifying specimens to family when the gills are small and hidden under sternite 10.