Ennomos erosaria

Ennomos erosaria, the September thorn, is a moth of the family Geometridae. It lives in the Palearctic realm, in western Europe and from central Scandinavia, and its range reaches the northern Mediterranean and east to the Caucasus and Russia, with the south eastern limit in Turkey. It is widespread in mixed and deciduous forests and favours dry deciduous forests and parks; in the Southern Alps it rises to about 1600 metres. The wingspan is 30 to 35 millimetres and the ground colour runs from straw yellow to ochre yellow with brown bands. The moths fly in one generation from July to October and come to light. The elongate larva, which closely resembles an oak twig, is brown with a tinge of purple or green and feeds on oak, birch and lime.