Wing span

Large, 66–75 mm (2.57–2.93 in.).
Wing upper side

Can be blackish or orangey brown (f. clytie). Forewing blackish brown with white blotches and hind wing with white strip. Pattern similar to orangey brown one but yellowish orange. Males’ wings with bluish violet sheen, depending on angle of view. Rear tip of forewing and hind wing with eyespots with black centre and orange ring.
Wing underside

Forewing orangey red, outermost part of leading edge of wing with white blotches and more inner part with black blotches. Hind wing with white strip. Rear tip of forewing with eyespot which has blue centre surrounded by black and finally white and rust-red. Hind wing mainly grey, white in middle or light grey strip and orangey brown strip in margin. Back corner of hind wing with one or two smaller eyespots (with blue and black pupil and yellowish orange iris).
Habitat

Broad-leaved forests.
Flying time

July.
Overwintering form

Caterpillar.
Larval foodplant

Aspen (Populus tremula) and goat willow (Salix caprea).

The lesser purple emperor is very rare but can be found in the south of Finland. It is not small, nor is it any smaller than the purple emperor, with which it can be confused as well as with the white admiral and the polar admiral. The white and poplar admirals completely lack the eyespots that are typical of the purple emperor, however. The lesser purple emperor has a very distinct eyespot on the upper surface of the forewing while the purple emperor only has one on its hind wing. Additionally, the white strip on the upper side of the purple emperor’s wings has more clearly defined borders. When seen from very close, a good identification marker between emperors and poplars is the colour of proboscis: emperors have yellow, admirals dark brown.

Females lay their eggs individually on the leaves of the host plant. The lesser purple emperor is an alien species in Finland which has become more abundant since the turn of the millennium.

Lesser Purple Emperor

Taxonomy

Order

Family

Subfamily

Genus

Species