Purple-bordered Gold Idaea muricata
Wingspan 18-20 mm.
This small Geometrid is found locally in the southern half of England and Wales, and rarely in Ireland.
Inhabiting heathland, fens and marshes, the adults fly from dusk onwards during June and July, and can sometimes be found on the wing at sunrise.
The larvae feed on marsh cinquefoil (Potentilla palustris) and overwinter in this stage.