This butterfly is active during both night and day. Males are brown to gray in colour and have distinctive large, broadly feathered antennae. The females are larger than males and are much lighter, almost white in colour. Once the female has laid her eggs, they are covered with a layer of hair from her own body. The caterpillar is gray to almost black in colour with light longitudinal lines on its body. Striking are the long hair and rows of dots on the body. The front knobs are a blue and the back are red to brown.

Between 35 to 55 mm wingspan.

Hibernation takes place as egg.

The caterpillars have no real preference as their food is concerned. They feed on many trees and shrubs the leaves and sometimes are able to make much damage.

Flight season
Between June and August.

Europe and Asia. In 1860 this species is introduced in North America and is still expanding its range.