Its colouration ensures it blends well with its preferred habitat rocky, open country in the high mountains.

This species was first described by Edward Meyrick in 1883 using specimens collected at Castle Hill by J. D. Enys and named Pasithea omichlias.

[4] George Hudson discussed and illustrated this species in his 1898 volume New Zealand moths and butterflies and referred to it as Notoreas omichlias.

Forewings moderate, hindmargin rounded; dark grey, irrorated with whitish; several obscure dark fuscous lines towards base; a slender curved dark fuscous fascia before middle; a blackish discal dot; a somewhat broader irregular subdentate dark fuscous fascia beyond middle, forming a short bidentate projection in middle, and a shorter simple projection towards costa; sometimes two pale lines beyond this, and a pale subterminal line; a blackish-grey hindmarginal line; cilia pale grey.

[8] Adults often settle on grey coloured rocks where its forewing pattern ensures it is well camouflaged.