The Cameo Crypsedra gemmea
Wingspan 42-44 mm.
There is just a single record of this species in Britain - one which occurred at Cockpole Green in Berkshire in September 1979.
It is becoming commoner on the Continent, including the Netherlands, where the photograph was taken, so it may soon reappear in Britain.
The species flies from July to September and the larvae feed on various grasses.