(Stephens, 1852)Wingspan 12-16 mm.
Generally distributed throughout the British Isles, this species has a tendency to be commoner around the coast and on chalky ground. It differs from similar species by its dark head and thorax.
The adults fly in two generations, in May and June, and again around August.
The larvae feed on common ragwort (Senecio jacobaea). Early brood larvae in July start on the flowers and complete growth in the main stem, causing a swelling with an obvious hole where pupation occurs in a yellowish brown cocoon. The later larval brood feeds in September and October in the stems and rootstock, and overwinters there until pupation in April.