Identifying features
Wingspan: 58-72 mm. Females are clearly the largest.
Similar species
Purple emperor can be confused with white admiral, Poplar Admiral, and lesser purple emperor. Their behaviour and appearance are so similar that they can be confused with lesser purple emperor and Poplar Admiral, and the two species cannot be reliably distinguished during flight.
Distribution
Denmark is located at the northern limit of the species' range. The first Danish record was made in 1872, in Sundby Storskov on the island of Lolland, from where it slowly spread.
Biology
Purple emperor overwinters as a small larva. The larva grows rapidly during the early summer, pupating in mid-June or late June.