is now generally acknowledged to be one of the most important branches of 

 zoological science, there still exists among the otherwise well informed a 

 complete ignorance and misconception of the main laws on which Pro- 

 tective Coloration is based. 



The present book has been constructed for two main purposes: First, to 

 lay before the comparatively few naturalists and others who have duly appre- 

 ciated the original articles on the subject, the results of my father's further 

 researches, with examples of the working of the newly revealed laws in many 

 branches of the animal kingdom; and second, to present the matter, both in 

 its simplest terms and variously elaborated, to a wider circle of readers. We 

 hope thus to clear the way to a more general understanding and more intelli- 

 gent study of the relations between animals' costumes and their environments. 

 As the book stands, although it has a far wider scope than the previously 

 published articles, it must be considered merely a fragmentary introduction 

 to the huge and fascinating subject of Protective Coloration. Fundamental 

 principles are defined, and many examples are given, both by illustrations 

 and in the text, of the workings of these principles on actual animals; but 

 nothing like an exhaustive examination of the species of any branch of zoology 

 has been attempted. 



For the most part, we do not draw hypothetical conclusions from facts; 

 but we reveal certain beautiful facts hitherto unknown; we disclose and ex- 

 plain the remarkable power of several naturally applied laws of optical illu- 

 sion — ^as these applications stand, by whatever causes produced, and as all 

 may see them. That is, we show and analyze the concealing- power of the 

 colors of animals as they exist to-day. 



The illustrations are of particular importance, inasmuch as they include 

 what we believe to be the first scientific paintings ever published of animals 

 lighted as they actually are in Nature. This will be explained in detail later 

 on. The colored pictures have been painted either from mounted specimens, 

 as in the cases of the Grouse, the Wood Duck, and the Peacocks, or from 

 live captives, as in the cases of the Snake and all the Caterpillars. The pic- 



viii 



