Wells provides the following caption for his figure 7.2:
Discrepancies in peppered moth distribution
Locations in the United Kingdom of some descrepancies
that didn't fit the classical story. (a) Manchester, where
the proportion of the melanics was never as high as
theory predicted; (b) East Anglia, where melanism was
hight despite lichen-covered tree trunks;
(c) South of latitute 52 degrees North where melanism
increased after the introduction of
pollution contrel; (d) The Wirral peninusla, where
melanism becan decreasing before lichens returned to the
trees.
