Scallop Shell Hydria undulata
Wingspan 25-30 mm.
A highly distinctive moth, unlikely to be confused with any other British species.
It prefers open woodland with an undergrowth of bilberry, and marshy areas, and flies in a single generation from June to July.
It occurs locally over a large part of the British Isles as far north as southern Scotland.
The larvae spin together leaves at the tips of shoots of sallow (Salix), and bilberry (Vaccinium myrtillus).