Local in woodland, in England, Wales and Ireland, but sparsely distributed. In Hampshire and on the Isle of Wight only two breeding colonies are known, in Parkhurst Forest on the Island and in Ashford Hangers on the mainland, but single specimens turn up from time to time all over the area. Wingspan 38-44 mm. Unmistakable. Larva feeds on Wych Elm and English Elm, over-wintering as a pupa.
The abundance in each month is indicated as follows:
No records Very occasional Irregular Uncommon Off-peak, but not unusual Off-peak, but not unusual Main flight time