Known for developing the concept of Mullerian mimicry, whereby poisonous species with a common predator display similar warning signals, the naturalist Johann Friedrich Theodor (Fritz) Muller (1821-97) spent most of his working life in Brazil. Having emigrated from Germany, owing partly to his radical atheism, he became a strong early supporter of Darwinism. Drawing on his studies of crustaceans, he originally published this work in German as Fur Darwin (1864), and sent the great naturalist a copy. Muller became a regular correspondent, and Darwin supported the translation of Muller's work,...

When I had read Charles Darwin's book 'On the Origin of Species, ' it seemed to me that there was one mode, and that perhaps the most certain, of testing the correctness of the views developed in it, namely, to attempt apply them as specially as possible to some particular group of animals. such an attempt to establish a genealogical tree, whether for the families of a class, the genera of a large family, or for the species of an extensive genus, and to produce pictures as complete and intelligible as possible of the common ancestors of the various smaller and larger circles, might furnish a...