PROTECTIVE MIMICRY. 413 



thus be more certainly deterred from the intended capture. The 

 bright yellow colour contrasting forcibly with the dark brown body 

 no doubt acts as a danger signal to a pursuing enemy. 



The possession of this additional protection would, of course, 

 operate to make Euplcea core additionally unpleasant to its enemies ; 

 and perhaps that is the reason why it is imitated in appearance 

 by more than one unprotected species. For instance, Papilio panop* 1 , 

 a butterfly about the same size, in the general brownish-purple 

 coloration of its upperside, and the row of whitish markings 

 round the posterior edge of the hindwings, bears a strong resem- 

 blance at a distance to Euploea core. So, again, in the light buff or 

 cream-coloured wings strongly veined with black of Papilio 

 dissimilis and clytia, as well as in their slow lazy flight, so unusual 

 in members of the genus Papilio, we trace a likeness to several 

 species of the Danais protected by their bad smell and taste. 

 These resemblances are the more interesting as they tend to show 

 that the likeness is a true imitation, the result of gradual evolution, 

 and not a mere persistence, or survival of or reversion to an old 

 type common to the whole race. For Euploea core and Hijpolimnas 

 bolina, though belonging to the different subfamilies of Danaince and 

 NymphalincE, are yet members of the same family of Nymphalidce . 

 It might, therefore, be plausibly argued that the resemblance 

 between them is but a reversion in both to some feature in a 

 common ancestor. But the members of the genus Papilio belong 

 to the wholly different division of the Papilionidce. If, then, we are 

 to infer that these resemblances are imitations evolved in the 

 process of time for the purpose of protection, we are led to the 

 conclusion that the imitating species is a later development than 

 the imitated. For it would only be after the latter had proved 

 by experience the value of the feature in which the resemblance 

 lies that it would be found of service to the former. We thus 

 arrive at an interesting conclusion regarding the relative ages of 

 different species, which would seem to show that the whole division 

 of Papilionidce is of later birth than the Nymphalidce — a theory 

 which seems to derive additional support from the fact that the first 

 pair of legs in the Papilionidce are strong and perfectly developed, 

 while in the Nymphalidce they n.re imperfectly developed, as though 

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