Grass Eggar Lasiocampa trifolii
([Denis & Schiffermüller], 1775)
Wingspan 40-55 mm.
In common with many of the Lasiocampidae, the females of this species are larger than the males, though otherwise similar in appearance.
The hairy caterpillars feed on a variety of grasses and plants.
It occurs rather locally, on coastal sand hills in the north-west and south-west of Britain, and flies at night in August and September, when it is attracted to light.