Around 9-10mm, a dark grey/black fly with a bold but short white stripe at the front of the thorax. The dark grey abdomen typically has a pale tip. The Morellia genus can be recognised by this generally dark colour, with vein m gently curving towards the wing margin and the middle tibia without a strong posteroventral seta, though posterodorsal and posterior setae usually well developed. Morellia simplex is probably the commonest of the genus and can be recognised by having a parallel-sided prosternum with lateral bristles.

Easily confused with Polietes domitor, but they are easily separated by the wing venation.

• Vein m gently curving
• Middle tibia without a strong posteroventral seta
• Posterodorsal and posterior setae usually well developed
• Overall appearance dark grey to black
• Prosternum parallel sided and with lateral bristles
• Grey dusting on the abdomen
• Grey dusting on the thorax visible when viewed from behind

It breeds in cattle dung so is usually found around cattle pasture.

Peaks in April/May and in August/September.

It is sometimes referred to as a Sweat Fly and it can be a particular nuisance to cattle.

Widespread and quite common in Britain.

Fairly common in Leicestershire and Rutland