Blue-winged Olive - Serratella ignita

Small to medium sized flies with three tails and large hind wings.  The sub-imago has dark blue grey wings and the tails are banded with brown.  Females have dark green eyes and the body is a greenish olive.  As the flight period progresses the body darkens to a rusty brownish olive.  The male has red eyes and the body varies between orange-brown and olive brown.  The last segment is often a much lighter shade. Nymphs have 4 pairs of gills and banded legs and tails.

Nymphs of this species live in fast flowing streams and rivers, especially where aquatic vegetation is present.  They are usually found clinging to, or crawling amongst submerged plants and stones, although they may swim in short bursts if disturbed. Adults can usually be found near to this type of stream.

There is one generation a year, which usually overwinters in the egg stage and emerges between April and September.

The nymphs feed by collecting or gathering fine particulate organic detritus from the sediment. 

Widespread and fairly frequent throughout Britain.

Fairly frequent in Leicestershire and Rutland.