Wingspan 75 to 95 mm. A very large species, superficially similar to some other Erebinae species, but the blue underwing colouration is unmistakable. 

Unless identified by a recognised expert, a photo is required.

Late August and September.

A former rare immigrant species, with periods as a scarce resident in the south and east. Now a recent colonist and resident over a much wider distribution.

Recent colonist to VC55.