Canary-shouldered Thorn Geometridae

Ennomos alniaria (Linnaeus, 1758)

Description: Wingspan 28-42mm.

Similar Species: Adults are similar to the August Thorn E. quercinaria, but are usually recognised by the canary yellow thorax which is quite hairy. The forewings are scalloped along the outer edges and there are also two cross-lines.

Key Identification Features:

Sets:  male upperside

Flight Period: Early August to late October; most commonly encountered during August and beginning of September.

Status: 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.

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

Bradley & Fletcher number: 1913 Agassiz number: 70.234

Additional information:

UK Moths account


 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland