Until recently, the only confirmed sighting of this species in Britain was a female caught in Shipbourne, near Sevenoaks, Kent on 2nd July 1953. However, in July 2014, an influx in the Netherlands presaged over 30 sightings of this species from a number of counties in south-east and east England, mainly in Norfolk but also as far north as Tyneside and west to Devon. Scattered sightings in March 2015 indicated that it can successfully overwinter in Britain. The first Hampshire record was from Whiteley Pastures on 19 April 2015, and given the condition of the insect, this was probably also an overwintering individual that had gone unnoticed the year before.
N. xanthomelas is very similar in appearance to the common and widespread
Small Tortoiseshell Aglais urticae but
xanthomelas tends to be larger, with yellow legs (giving its other vernacular name, Yellow-legged Tortoiseshell) and a yellow patch on its upper forewing instead of white.
Resident in central and eastern Europe, but occasionally sighted in Finland, Denmark, Germany and Sweden. Larva feeds on willow and poplar.