Apatura iris is widely distributed in dense, broadleaved woodlands throughout Europe including southern Britain, and across the Palearctic region to central and western China. 
   Adults have dark brown wings with white bands and spots, and a small orange ring on each of the hindwings. Males have a have a purplish blue sheen caused by iridescence that the slightly larger  females lack. 
   The caterpillars are green with white and yellow markings, and have two large horns at the anterior end and a smaller one at the posterior.
   Females spend most of their lives in the tree canopy, preferring dense, mature oak woodlands, coming down only to lay their eggs on the small willow bushes that grow in clearings and bridleways.
   Males also spend much of their time in the tree tops, defending their territory from rivals, though they will sometimes descend to drink from puddles or feed.
   Unlike most butterflies, the purple emperor does not feed from flowers but instead on the honeydew secreted by aphids, sap oozing from oak trees, and on dung, urine, and animal carcasses.
   Females lay eggs in late summer on the upperside of Sallow leaves, preferring the broad-leaved Sallow, (Salix caprea), but they will also use the narrow-leaved Sallow, Salix atrocinerea, and various species of Poplar. (Poplar is more common in continental Europe than in the British Isles.) 
   After hatching, the larvae will lie along the middle spine of the leaf where they are well camouflaged, and feed only at night.
   During winter they hibernate in the forks of Sallow branches, where they change color from green to brown to match their surroundings.
   The following June they form a pale green chrysalis, looking somewhat like a leaf shoot.
   Adults usually emerge in July, flying well into August.