The wingspan is 22–27 millimetres (0.87–1.06 in). 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. The larva is stout, slightly tapering
at each end, rugose, with conspicuous tubercles and setae. It is reddish-ochreous or brownish ochreous with an interrupted grey dorsal line. The lateral and ventral surfaces are mostly dull reddish; tubercles black. The pupa is rather stout, bright red or red-brown, the abdomen darker.[1]
Adults are in wing from May to August in one generation.
The larvae feed on Galium species. Larvae can be found from September to May.
Subspecies
Colostygia olivata olivata
Colostygia olivata gigantea Pinker, 1953
References
^Prout, L. B. (1912–16). Geometridae. In A. Seitz (ed.) The Macrolepidoptera of the World. The Palaearctic Geometridae, 4. 479 pp. Alfred Kernen, Stuttgart.pdf