The adults are 6mm long with a black thorax covered in a sheen of golden hairs. Usually appearing in great numbers after periods of cold weather with a slow and sluggish flight.
The larvae are parasitic and therefore difficult to monitor or control. Adults will spend the majority of the year outside and only come into close contact with humans during the late autumn when they look to overwinter.
Large numbers of adults will cluster into cracks and crevices in houses, usually most commonly found in window edging or in roof spaces.
1. The British Pest Management Manual. Section 5, pg 151.
2. Lab notes, Tarakan International.