Rare immigrant from North Africa, appearing in southern England in small numbers. In 1969 at least ten were reported; although the records were spread over eight weeks, the concentration in mid-October appears to have been part of a very large immigration which included other scarce species. In Hampshire and on the Isle of Wight there have been about ten records to date. Wingspan 38-48 mm. The far more common Burnished Brass Diachrysia chrysitis
has the thorax and abdomen stouter and forewing broader, with basal portion of the metallic patch extending from costa to dorsum; in Slender Burnished Brass most of the forewing is filled by a triangular greenish-brassy area, narrowly bordered at termen, more broadly at costa and dorsum, with pale purplish grey (MBGBI Vol 10). Larva polyphagous, no evidence of breeding in the UK.