THEORIES OF MIMICRY 551 



The universal tendency of common habits and environment to be 

 accompanied by common form and appearance has long been a familiar 

 fact, and no one would have conceived of a vast gap in this tendency 

 but that naturalists thought themselves forced to accept the evidence 

 that such a gap existed, and set themselves to work to fill it as best they 

 could. Now, however, the obstacle to their discovering the wholly con- 

 cealing character of the whole array of costumes that had puzzled them 

 vanishes, and no power can withhold this array from taking its place 

 in the ranks of universal procryptic coloration. 



The following pages demonstrate that all diversification of the 

 colors of animals' costumes tends wholly and unmixedly to conceal 

 them. This should set the believers in conspicuous species reflecting 

 that while they are making their records of cases of momentary con- 

 spicuousness of individuals of one species or another, they are making 

 no investigation whatever of the possibility that all the while a large 

 number of individuals of this same species are, through some magic 

 of their costume, escaping their sight and making no impression 

 on their minds. It is precisely to such an investigation as this that I 

 here invite the reader. 



Any out-of-door naturalist knows that if he walk through a sunny 

 field of fairly profuse vegetation, after first studying it, say, from an 

 upper window, he will flush an immensely greater amount of so-called 

 conspicuous aerial life than he had detected from the window, and he 

 will believe that much of this life was all the time within the field of 

 his vision. 



These plates have been prepared with the especial purpose of ex- 

 posing the weakness of the optical hypotheses upon which the theories 

 of " warning-colors," " recognition," " mimicry," etc., so largely rest. 

 They show that these hypotheses would never have lived a day had their 

 originators begun by testing them. Darwin's erroneous supposition 

 that a conspicuous mark on an object makes the object itself conspicuous 

 has been built on and rebuilt on by the leaders of zoological research, 

 even down to the present day. Entomologists, especially, make much 

 of the supposed power of sharp and strong patterns to render con- 

 spicuous that particular part of the insect which they occupy. "We now 

 discover that the effect of these patterns is the very opposite. In the 

 illustrations of this article we see the actual effect of such marks in 

 several typical situations. Fig. 1 shows two butterflies and several 

 letters, all of one color, and against one background. On each butterfly 

 and on several of the letters bright spots or patterns have been painted. 

 As the spectator recedes, those parts of the butterflies nearest the bright 

 patterns fade, until, at a short distance, they are invisible, while the 

 rest of the insect is clearlv distinguishable up to a much greater dis- 



