106 , THE EVOLUTION THEORY 



in a fifth case, the nocturnal Hyelosia heliconoides Swains., the same 

 thing has happened as in Castnia, but the scales are also fewer in 

 number. Thus in each of the mimics the changes which have taken 

 place in the scales are quite different, but they bring about the same 

 effect, the glass-like transparency of the wings, on which the re- 

 semblance to the model depends : what we have before us is, therefore, 

 not a similarity of variation, but only an appearance of similarity in 

 external features. 



In the face of such facts there can be no further question of the 

 often repeated objection, that the resemblance of model and copy 

 depend on the similarity of external influences upon species living 

 in the same latitude, even if that were not already sufficiently refuted 

 by the frequent restriction of the mimicry to the female. And that 

 mimicry should be a mere matter of chance is negatived even by the 

 single fact that model and copy always live in the same area, arid that 

 the local varieties of the model are faithfully followed by the mimic. 

 An interesting example of this is furnished by Elymnias undularis, 

 already mentioned, for in this ease the female (PI. II, Fig. 33) mimics 

 the brown-yellow Danais plexippus (PI. II, Fig. az), not wherever 

 E. undularis occurs, but only in Ceylon and British India. In Burmah, 

 where another Danaid, I), hegesip'pus, is common, it mimics that; and 

 in Malacca it does not copy a Danaid at all, but resembles the male 

 of its own species, which in India is very different from it, since 

 there the female mimics one of the blue iridescent Euplceje (PI. Ill, 

 ^ig- 34)- It cannot therefore be a matter of ' chance,' and we should 

 have to give up all attempt at a scientific interpretation if we were not 

 prepared to accept that of natural selection. Even the interference of 

 a purposeful Power can hardly be seriously considered in this case, 

 even by those who are inclined to such a view, for the gradual 

 approximation to the model, which is a matter of course in a process 

 of evolution, could only appear, if referred to the benevolent intel- 

 ligence of a Creator, as an unworthy trick, designed to lead humanity 

 astray in its strivings after knowledge. On the other hand, this 

 gradual increase of resemblance, which becomes apparent when we 

 compare several mimetic species— this carrying over, step by step, 

 from the female to the male— and many other facts point to the 

 working of natural forces according to law, and, if there is to be 

 found anywhere in living nature a complicated process of self- 

 regulation, it certainly lies before us here, clearer and less open to 

 objections than almost anywhere else. I do not mean to say, however, 

 that we can verify it statistically in detail, as has been demanded by 

 the fanatical opponents of natural selection. A direct testing of 



