75 - 84mm
A large butterfly; the male is famous for the deep purple sheen which shows up as the light catches its wings. At certain angles this can appear black, but suddenly it can shine with a deep lustre. Across this are white marks, three rows of a few slashes on the forewings and a continuous bar on the hindwings. The female is slightly larger with a 84mm wing span, larger white marks and band but has only a dull, dark-brown ground colour. Both have an orange tinge at the tail and a small orange circle nearby on the hindwing. The undersides of both sexes are roughly similar with a pale fulvous ground colour, white marks and a prominent orange circle on the forewings and a large white band across the hindwings.
The flight season is usually from the first week of July, through to the beginning of August.
The Purple Emperor may not come down from its preferred lofty situation among the crowns and canopies of old oak-woods.
Some nectaring will occur on available woodland flowers, particularly bramble. The males, and also females, will come down to ground level to seek moisture, particularly from animal droppings or even rotting carrion.