Description: Wingspan 34-45 mm. Forewing colour is variable from pale to dark grey. The antemedian and post median lines are darker than ground colour. There is a black basal streak which is clearly forked at the apex. There are two dagger-like tornal marks on the forewings and the subterminal line is incomplete and not clearly defined. The stigmata are paler and outlined in black at the distal margin. Hind wings pale fuscous with darker veining. Mid-May to early August.

World Distribution: Throughout western Europe from southern Spain to Finland.

Irish Distribution: Widespread throughout all counties but more frequent in Down and Armagh.

Ecology: An early summer species found mainly in woodland and a variety of other habitats including some suburban gardens. Adults appear at light frequently, but in small numbers. The colourful larvae are easily found throughout their development. They feed from July to early October on many species of trees and shrubs including birch Betula spp., oak Quercus spp., elm Ulmus spp., Hawthorn Crataegus monogyna, Blackthorn Prunus spinosa. It overwinters as a pupa.

Key Identification Features:

• Dagger-like marks at the tornal border
• Pale stigmata finely outlined in black
• Pale fuscous hindwings

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

iNaturalist: Acronicta psi at iNaturalist World Species Observations database.