COLOR AND TATTERX IX AXIMAL9 42o 



a high dcgee of speciahzatiou lias been assiiinod, by nearly all 

 upholders of the use hypotheses, to l)e natural selection. This 

 agent can account for i)uri)()sefulness, which is obviously an 

 inherent part of all the hypotlieses. And no other su^^ested 

 agent can. Weismann makes, indeed, of this fact, ))y inverting 

 the problem, one of the most efifective arguments for the potency 

 and " Allmacht" of natural selection. He declares tliat tbfc 

 existence of special })rotective resemblanc(% warning colois, 

 and mimicry proves the reality of selection. But it must Ikj 

 asked, while admitting the cogency of much of the argument 

 for natural selection as the eflicient cause of high speciaHzation 

 of color and pattern as we have seen it actually to exist, how 

 such a condition as that shown by the mimicking viceroy butter- 

 fly has come to be gradually developed — gradual (h'velopment 

 being confessedly selection's only mode of working. Could the 

 viceroy have had any protection for itself, any advantage at all, 

 initil it actually so nearly resembled the inedil)le monarcli a3 

 to be mistaken for it? No slight tinge of brown on the black 

 and white wings (the typical color scheme of the genus), no 

 slight change of marking, would be of any service in making 

 the viceroy a mimic of the monarch. The whole leap from 

 typical Basilarchia to (apparently) typical Anosia had to 1x3 

 made practically at once. On the other hand, is it necc^vsary 

 for Kallima, the simulator of dead leaves, to go so far as it has 

 in its modification? Such minute points of detail are there 

 as wdll never be noted by bird or lizard. The simple necessity 

 is the effect of a dead leaf; that is all. KalUtna certainly does 

 that and more. Kallima goes too far and proves too much. 

 And there are other cases like it. Natural selection alone coukl 

 never carry the simulation past the point of advantage. 



But whatever other factors or agents have })layed a part in 

 bringing about this specialization of color and j^atttTU, exem- 

 plified by animals showing protective resemblances, warning 

 colors, terrifying manners, and mimicry, natirr; 1 selection liiuj 

 undoubtedly been the chief factor, and the basis of utility 

 the chief foundation, for the development of the specialized 

 conditions. 



