50 DARWINISM TO-DAY. 



larchia type of colour and pattern; on the contrary, you 

 find an extraordinarily faithful imitation (duplication) of 

 Anosia' s colour and pattern. Only in a narrow black trans- 

 versal streak across the outer disc of each hind wing is there 

 any divergence in the viceroy from the Anosia pattern. 

 Now Anosia is distasteful to birds ; after a few experiments 

 with Anosia a bird recognising this ill-tasting morsel in its 

 conspicuous red-brown livery leaves the monarchs alone. .Not 

 only monarchs, however, but also viceroys, which are to all 

 external seeming only slightly smaller monarchs. The viceroy 

 is, however, not distasteful ; it would be a welcome bonne 

 bouche to any bird that could distinguish it. But thanks to 

 its perfectly mimicking colour-pattern it wings its deceitful 

 way unmolested. There is huge usefulness here, and selec- 

 tion can well be the steadfast maintainer of the viceroy's 

 dissimulation. But of what avail for this purpose of deceit 

 was the first tiny tinge or fleck of red-brown on the staring 

 black and white wings of the ancestral viceroy? How can 

 one possibly conceive of an attainment of this identity of 

 pattern between mimicker and mimicked by selection on a 

 basis of life-or-death-determining advantage of slight chance 

 appearances of brown or reddish flecks or tinges in suc- 

 cessive viceroys? Not until practically full development of 

 the mimicry pattern existed can this pattern have worked its 

 advantage. It is, indeed, a different matter with many, per- 

 haps most, cases of general or special protective resemblance. 

 A little green, a little brown could obviously help the insect 

 living in green foliage, or on the ground. Every change of 

 tinge toward the general environing colour is worth while ; it 

 helps melt the insect into its inanimate surroundings. But 

 with mimicry it must be the whole thing or nothing; or at 

 least near enough to the whole thing to pass for it. Wolff 

 puts the objection about as follows : There are compound 

 organs and complex adaptations, whose complication (he 

 would better say, whose advantage due to complication) can 



