I will now give the date and mode of publication of each of the essays in this volume, as well as the amount of alteration they have undergone.
I.—On the Law which has Regulated the Introduction of New Species.
First published in the “Annals and Magazine of
Natural History,” September, 1855. Reprinted without alteration of the text.
II.—On the Tendency of Varieties to Depart indefinitely from the Original Type.
First published in the “Journal of the Proceedings of the Linnæan Society,” August, 1858. Reprinted without alteration of the text, except one or two grammatical emendations.
III.—Mimicry and other Protective Resemblances among Animals.
First published in the “Westminster Review,” July, 1867. Reprinted with a few corrections and some important additions, among which I may especially mention Mr. Jenner Weir’s observations and experiments on the colours of the caterpillars eaten or rejected by birds.
IV.—The Malayan Papilionidæ, Or Swallow-Tailed Butterflies, as Illustrative of the Theory of Natural Selection.
First published in the “Transactions of the Linnæan Society,” Vol. XXV. (read March, 1864), under the title, “On the Phenomena of Variation and Geographical Distribution, as illustrated by the Papilionidæ of the Malayan Region.”
The introductory part of this essay is now reprinted, omitting tables, references to plates, &c., with some additions, and several corrections. Owing to the publication of Dr. Felder’s “Voyage of the Novara”