Colostygia olivata, the beech-green carpet, is a moth of the Geometridae family. It is found in most of Europe. The wingspan is 22–27 mm. Freshly hatched moths have green forewings.There is a darker, brown central band narrower towards the centre of the forewings.This band is edged with a white wavy line. The hindwings are smoky grey with a pale crossline. Adults are in wing from May to August in one generation. The larva feed on Galium species. Larvae can be found from September to May.