- PROSOPISTOMATIDAE

Mayflies

Code QE099999

This is not an adult beetle but an aberrant form of larval mayfly, Order : Ephemeroptera. The head is short, somewhat deflexed, and closely apposed to the thorax. The body outline is smooth and rounded like that of an oval-shaped beetle, with 'elytra' covering all but the terminal 1-3 segments of the abdomen. The terminal segments of the abdomen look unusually narrow for an adult beetle, and may end in a tuft of sparse setae.

The apparent 'elytra' are formed by a carapace-like projection of the thorax, and do not separate down the mid-line. On the underside: Thoracic and abdominal segments are clearly visible, with the first abdominal segment fused to the thorax. There are either no lateral abdominal gills of the type generally seen in Ephemeroptera, or only short gills.

Prosopistomatidae are known from running waters in northern Australia. They are regarded as rare.