Common on calcareous grassland, heathland, moorland, woodland rides, sand-dunes and sea cliffs throughout the British Isles. Widespread and common in Hampshire and on the Isle of Wight. Wingspan 37-43 mm. Very similar to Lesser Treble-bar A. efformata, which see. Larva feeds on St John's-wort.
The abundance in each month is indicated as follows:
No records
Very occasional
Irregular
Uncommon
Off-peak, but not unusual
Off-peak, but not unusual
Main flight time