VI PREFACE. 



Natural History," September, 1855. Reprinted with- 

 out 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 Linnsean 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 a 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 experi- 

 ments on the colours of the caterpillars eaten or 

 rejected by birds. 



IV. THE MALAYAN PAPILIONID^E, OR SWALLOW- 

 TAILED BUTTERFLIES, AS ILLUSTRATIVE OF THE 

 THEORY OF NATURAL SELECTION. 



First published in the " Transactions of the Lin- 

 nsean Society," Vol. XXV. (read March, 1864), under 

 the title, " On the Phenomena of Variation and Geo- 

 graphical Distribution, as illustrated by the Papilionidas 

 of the Malayan Region." 



The introductory part of this essay is now reprinted, 

 omitting tables, references to plates, &c., with some ad- 

 ditions, and several corrections. Owing to the publi- 



