Introduction: Mutation, Mendelism, and natural selection.--A naturalist's contribution to the discussion upon the age of the earth. (Liverpool, 1896)--"What is a species?" (London, 1905)--Theories of evolution. (Boston, 1894)--Theories of heredity. (Oxford, 1889)--The bearing of the study of insects upon the question 'Are acquired characters hereditary?' (London, 1905)--A remarkable anticipation of moderm views on evolution. (1897)--Thomas Henry Huxley and the theory of natural selection. (Birmingham, 1905)--Natural selection the cause of mimetic resemblance and common warning colours. (London, 1898)--Mimicry and natural selection. (Berlin, 1901)--The place of mimicry in a scheme of defensive coloration. (Leeds, 1890)--Appendix: A classification and index of the examples of mimicry quoted in the text.--Analytical index