White-spotted Pinion Cosmia diffinis
Wingspan 29-36 mm.
The rarest and most attractive of the four british Cosmia species, this moth underwent a rapid decline as a result of Dutch elm disease during the 1970s.
The moth is now scarcely distributed in parts of southern England. The flight period is from July to September, and the species is attracted to light.
The green caterpillars have pale stripes, and feed on English elm (Ulmus procera) and wych elm (U. glabra), seemingly preferring the suckers growing from the trunks, known as epicormic growth.