Nationally scarce (Nb) in open areas with scattered trees in central and southern England, though also recorded from Durham and north and south Wales; local in Ireland with scattered records from a few eastern and southern counties (MBGBI Vol 2). In Hampshire known from only a handful of sites, notably at Chilbolton, where known for many years. Not recorded from the Isle of Wight to date. Wingspan 33-46 mm. Day-flying. Mainly recorded in the larval form, but the early stages are difficult to find during the winter months and the species' true distribution remains largely unknown; the use of the HOR pheromone lure is expanding our knowledge of the true distribution of this spectacular insect. Larva feeds within wood of Black Poplar and other poplars, over-wintering two or three times.