Description: Wingspan 28-42mm. Early August to late October; most commonly encountered during August and beginning of September.

World Distribution: Across central Europe as far east as Russia.

Irish Distribution: Widespread through southern counties, but more local further north, where it may be under-recorded.

Ecology: An attractive species, which has a similar distribution and flight period to the August Thorn E. quercinaria. The brightly-coloured adults occur in a wide range of habitats, particularly woodland, heaths and bogs. They come frequently to light in moderate numbers. The larvae can be found from May to July on a variety of trees including birch Betula spp, willow Salix spp., Alder Alnus glutinosa and lime Tilia spp. It overwinters as an egg.

Key Identification Features:

• Vivid yellow thorax; heavier bodied
• Both wings heavily speckled and with scalloped edges
• Two crosslines on forewings

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

iNaturalist: Ennomos alniaria at iNaturalist World Species Observations database.