Description: Wingspan 26-35mm. Freshly emerged adults have green forewings green with a darker, normally brown central band which is edged with a white wavy line. The hindwings are normally smoky grey. Not known with certainty in N. Ireland. Skinner gives July and August as the main period.

Irish Distribution: Currently unknown. There have been a couple of recent claims of this species, but these are considered extremely doubtful. Formerly recorded from Tempo, Fermanagh in 1894 by Sir Charles Langham, Glenarriff, Antrim in 1895 by C.W. Watts, and Murlough Bay, Antrim by Cannon G. Foster in the early 1940s. There is also an unsubstantiated record from Murlough NNR, Dundrum in the late 1970s. It has not been refound at some of its former sites despite much fieldwork, which suggests it may have died out.

Ecology: An elusive species that seems to have a preference for coastal localities and woodland. It apparently rests during the day on rocks, stones walls and the trunks of trees. The larvae feed on bedstraws Galium spp. It overwinters as a larva.

Key Identification Features:

• Adults are green-coloured when fresh
• Dark central band, narrower towards the centre of the forewings
• Hindwings smoky grey with a pale crossline

Distribution Map from NBN: Colostygia olivata at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Colostygia olivata at iNaturalist World Species Observations database.