Haematopota pluvialis, the common horse fly or notch-horned cleg fly, or simply cleg in Scotland and northern parts of Ireland, is a species belonging to the family Tabanidae subfamily Tabaninae.

In males, the eyes touch at the centre of the frons and the colored stripes are restricted to the lower part.

The abdomen shows a dark background with a series of lateral pale spots and clearer bands at the end of each black segment.

[5] The males are harmless and feed on nectar,[7] while the females feed on mammal blood (hematophagy) (hence the Latin name Haematopota pluvialis, literally meaning 'blooddrinker of the rains'), mainly cattle and horses, needing blood for developing eggs.

When they bite they inject fluids inhibiting the coagulation of blood, which flows out in such a way that allows the horsefly to lap it.