Wingspan c. 15-22mm.
This rather scarce species occurs in the east and south-east of England, southwards to Devon, occupying dry, sandy habitats such as downland or breckland.
Externally, smaller specimens can resemble the rarer O. laetus, a presumed migrant species which has turned up several times mainly on the south coast, and genitalia examination may be necessary to be sure of identification.
The larvae feed on a number of foodplants, including mouse-ear hawkweed (Pilosella officinarum) on the leaves or flowers.
Adult moths fly between May and August, in two generations.
Gen. preps (Dissection Group website):