Figure 11.2: Two peppered moths (Biston betularia) rest on the dark bark of a tree in a highly polluted area near liverpool (top); the melanic, or carbonaria, form is better camouflaged than the light, typica, form. On the light-coloured, lichen coated bark of a tree in an unpolluted area of rural Wales the light form is almost invisible (bottom). Note that the original figure was published upside down (moths normally rest on trees pointing upwards). (Copied from Bishop & Cook 1975. Moths, melanism and clean air. Scientific American 232: 90-99. With the permission of Scientific American and the surviving author, Dr. Lawrence M. Cook)