. . .South European form of our red-admiral butterfly—is permanently smaller in the small and bare island of Porto Santo than in the larger and more wooded adjacent island of Madeira.

A very good example of comparatively recent divergence of character, in accordance with new conditions of life, is afforded by our red grouse. This bird, the Lagopus scoticus of naturalists, is entirely confined to the British Isles. It is, however, very closely allied to the willow grouse (Lagopus albus), a bird which ranges all over Europe, Northern Asia, and North America, but which, unlike our species, changes to white in winter. No difference in form or structure can be detected between the two birds, but as they differ so decidedly in colour—our species being usually rather darker in winter than in summer, while there are also slight differences in the call-note and in habits,—the two species are generally considered to be distinct. . . . Read More