A generally distributed and not uncommon species in areas of damp, undisturbed pasture and thin woodland, reaching to the moorland verges. [...] At elevation, and more particularly in the west, it is univoltine flying in July and early August, with virtually no overlap with the bivoltine form. The distinction between these individuals (all large pale specimens) and D. florida (q.v.) is by no means clear, and requires further elucidation. This is a promising field of research for the amateur (or professional) entomologist, and here in the north-east is the right area in which to undertake it! The species is [...] widespread in Durham, right up to Langdon Beck, Forest-in Teesdale, where July catches are the more usual, indicating that it is univoltine there. In the lowland area of the Wear valley it is normally bivoltine [...].