Colostygia olivata, the beech-green carpet, is a moth of the family Geometridae.

There is a darker, brown central band narrower towards the centre of the forewings.

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 pupa is rather stout, bright red or red-brown, the abdomen darker.