A beautiful butterfly, with inky black upperwings that turn deep purple as they catch the sun. In the male this colour is deeper and occurs over all the wings apart from the margins - the purple on females is a large blotch on each forewing, which is visible even in dull light. The underwings are a silver-grey with a white streak and a single black-pupilled orange eye beside the tail.

Dimensions:
Adult wingspan: 31-40mm.

National:
This hairstreak is locally common in England and Wales and into Scotland. It inhabits woodlands with Oak.

At Durlston:
It used to be found in the Aviaries and near Durlston Castle and may still be present as evidenced by recent reports. A small colony was discovered in Small Copse in 2006.

There is a single generation with adults emerging from early July to mid September. The eggs are laid on the Oak buds or the base of leaves and then remain dormant until the spring. The larvae emerge when the tree bursts its buds. The larva burrows into the flower bud and feeds inside until the first moult thereafter it lives inside a silken cocoon. The larvae pupate on the trunk of the tree or on the ground where they may be attended by to by ants.