Photo © Patrick Clement
Lampropteryx otregiata, the Devon carpet, is a moth of the family Geometridae. It is found from western Europe (from Scandinavia south to the Alps) to Japan and the Kuril Islands.
The wingspan is 27–30 mm. There are two generations per year, with adults on wing in May and June and again in August and September.
The larvae feed on Asperula and Galium species (including Galium palustre and Galium uliginosum). Larvae can be found from July to August. It overwinters in the pupal stage.
Source: Wikipedia
The primary larval foodplant is Common Marsh-bedstraw (Galium palustre).