Ecdyonurus venosus


The larvae of this mayfly is about 1 cm long and patterned with light and dark browns, it has a large rounded head and upward facing eyes. There are three long tail filaments.


The larvae live on the underside of rocks in clear streams

When to see it

Usually seen between summer and autumn

Life History

A study of nymphs has shown the presence of two definite broods of flies a year. The first swarms appear in June, the second from July to October. The early summer eggs hatch and emerge as flies within two months, whereas the autumn ones grow much more slowly and emerge the following June.

UK Status

Thought to be fairly common in Britain, although most records are from northern and western regions.

VC55 Status

Fairly common in Leicestershire and Rutland.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map