Description: Wingspan 25-29mm. Adults are olive green when freshly emerged. The dark cross-lines are wavy and dotted with black. The ground colour tends to fade fairly quickly after emergence giving a totally different appearance to the moth and may result in misidentification. Most adults captured at light tend to be light brown, often with little sign of the olive green colour. early April to the beginning of September although more frequent in late spring.

World Distribution: Throughout Europe to western India and Japan.

Irish Distribution: Widely distributed (but never commonly encountered) in southern counties particularly Down and Fermanagh. It was previously considered extremely scarce, however targeted fieldwork in some of the well-known sites has recently produced a number of records. It may exist more widely in some other mature woodland sites if looked for at the appropriate time.

Ecology: A spring species normally associated with well-established mature woodland where Holly Ilex aquifolium is common. Adults are attracted to light in very small numbers. It often rests during the day on the trunks of trees. The larvae can be found in June and July on Holly, Ivy Hedera helix and Wild Privet Ligustrum vulgare. It overwinters as a pupa.

Key Identification Features:

• Olive green when freshly emerged; colour fades quickly
• Often looks pale brown with dark cross-lines when seen at light
• Hindwings pale grey

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

iNaturalist: Acasis viretata at iNaturalist World Species Observations database.