Satin Wave Idaea subsericeata
Wingspan 22-25 mm.
A fairly plain-looking moth, which has a glossy sheen to the upper wing surfaces.
It frequents open, grassy areas and downland, and is relatively common in the south of England, becoming scarcer further north to southern Scotland. It also occurs locally in Ireland.
The adults fly in June and July and the caterpillar, which hibernates during the winter, feeds on low plants including knotgrass (Polygonum), dandelion (Taraxacum), and chickweed (Stellaria).