Melanic morph frequency in the peppered moth in the Manchester area

Abstract
Data are presented for the Manchester area, showing the recent change in frequency of the melanic morph carbonaria of the peppered moth Biston betularia (L.). The frequency has fallen from 90– in 1983 to below 10% at present; this decline shows that the phenomenon of industrial melanism, first noted in this species in Manchester, is now almost past.