Upperside of wings brown with yellow markings. Rapid, darting flight.
Wingspan 29 - 31mm.
Ova laid singly on underside of blade of purple moor-grass; also found on false brome. They hatch out after about 10 days.
Larvae, fully grown by October, hibernate. Larval stage lasts 10 months, pupation occuring early April.
Pupae, resembling withered grass, remain in this stage for about 6 weeks.
Generally from mid May to late June.
Found in several suitable sites in Fort William area, including Allt Mhuic Reserve at Loch Arkaig.