The Upper wings o this species are evenly brown.These butterflies live in colonies and seldom stray from their host tree exceptt to feed on bramble nectar. they fly in July. The larval forms feed on foodplants such as English Elm (Ulmus procera), Small-leaved Elm (Ulmus minor) and Wych Elm (Ulmus glabra).
The names of this butterfly refer to the white letter "W" that appears as a hairline streak on the underside hindwings. It is generally found in discrete colonies and rarely strays far from its food plant. It tends to remain in the canopy but may be forced to ground level in very hot years.
Woodland edges and woodland glades. This Hairstreak breeds only on elms whether stand alone elms in open habitats are sometimes used, but most colonies originate from English in hedgerows on elm sucker growth or young wych elms within woods. The butterfly requires flowering elms on which to breed. Unfortunately native elms fall victim to disease only a few years after first flowering, so the colonies are short-lived.
These pictures where taken in the Hot July of 2006 and it is clear that they have been driven down in search of ground moisture as they spend most of the time motionles on the tree canopy.