Small Scallop Idaea emarginata
Wingspan 22-25 mm.
Occupying damp deciduous woodland, meadows and marshes, this fairly distinctive moth occurs widely but never commonly in England and Wales.
It flies between June and August after dark, when it can be attracted to light, but it can also be flushed in the daytime.
The caterpillar is brownish and believed to feed on bedstraw (Galium) in the wild, though in captivity it can be reared on a number of plants, preferring withered leaves.