Sepsis cynipsea


A small blackish fly. It is about 2.5 to 3 mm long and has dark wing spots (one on each wing) typical of the Sepsis genus. This is a difficult group to identify and specimens really need microscopic examination to arrive at the species. Males of Sepsis cynipsea have an obvious notch part way down the front tibia which is unique within the genus.

Identification difficulty
Recording advice

Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.


Around fresh dung.

When to see it

Although the species might be encountered at any time, the main period is between May and September with a peak in July and early August.

Life History

The flies are active by day, and the sexes usually meet for mating around fresh dung where the eggs will be laid.

UK Status

Widespread and fairly frequent in Britain.

VC55 Status

Fairly frequent 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