144 CONCLUSION [ch. 



mimetic likeness bit by bit it will merely have con- 

 served and rendered numerically preponderant a like- 

 ness which had turned up quite independently. The 

 function of natural selection in respect of a mimetic 

 likeness lies not in its formation but in its conservation. 

 It does not bring about the likeness, neither does it 

 accentuate it: it brings about the survival of those 

 forms which happen to shew the likeness. Why vari- 

 ations on the part of one species should bear a strong 

 resemblance to other, and often distantly related, 

 species is another question altogether. 



Even a superficial survey of the facts makes it 

 evident that cases of mimicry tend to run in series — 

 that a closely related series of mimics, though often of 

 very different pattern and colour, tends to resemble 

 a closely related series of models. In Asia we have 

 the Cosmodesmus Papilios mimicking a series of 

 Danaines, while the true Papilios (cf. Appendix II) 

 tend to resemble a series of the less conspicuous mem- 

 bers of the Pharmacophagus group. In the same 

 region the various species of Elymnias form a series 

 resembling a series of Danaines. In Africa there stands 

 out the Cosmodesmus group again mimicking a Danaine 

 series, and in part also an Acraeine series. Over- 

 lapping the Acraeines again are various forms of the 

 Nymphaline genus Pseudacraea. It is also of interest 

 that in Danais chrysippus and Acraea encedon the 

 Danaine and Acraeine series overlap (cf. PI. IX). Similar 

 phenomena occur also in South America, where closely 

 parallel series of colour patterns are exhibited by several 



