Wingspan c.25 mm.
The combination of bold white longitudinal streak with an angled offshoot, and the dark blotch near the apex of the forewing make this a distinctive species amongst the Crambinae.
It frequents dry or sandy heaths with a proliferation of wavy hair grass (Deschampsia flexuosa), and although not well described, it is believed that the larvae feed on this grass.
The species is distributed locally in suitable habitat in England and southern Scotland and has also been recorded from Ireland. There is a single generation, with adults flying in July and August, when it can be attracted to light.