MIMETIC ASSOCIATIONS 



53 



one of which, P. adamastor, bears a very close resemblance on both surfaces to the common 

 Pseudacraea lucretia. In South Africa P. leonidas is represented by the variety brasidas, 

 which differs principally in having the spots creamy white instead of green, though in some 

 specimens the spots in the fore- wings are fewer, smaller, and arranged in a much more Amauris- 

 like pattern. The actual model of brasidas seems doubtful, but no doubt its general appear- 

 ance suggests the pattern of several of the black pale spotted Danaines which form the models 

 for so many African mimics. In his work on South African Butterflies, Trimen describes it as 

 a mimic of Amauris echeria, and states that it settles * precisely in the way affected by the 

 Amauris, viz. on a projecting leaf or twig with the wings closed and hanging downward, 

 and in this exposed position remaining motionless for a considerable time. On more than 

 one occasion I have mistaken brasidas when so posed for echeria '. The variety brasidas 

 would seem to be an edible species. Marshall found ' that it was promptly eaten by 

 a mantis, a spider, and a ground hornbill '. In connexion with the mimetic tendencies 

 of the species we have the following interesting comment by the above author (Trans. 

 Ent. Soc, p. 507, 1902). 



' I have always been struck with its {leonidas) marked difference in habit from the 

 southern brasidas. Its flight is strong and rapid, and it always goes straight ahead like 

 P. folicenes and P. antheus, which it somewhat resembles on the wing, in spite of its very 

 different shape. Brasidas on the other hand, has a slow sailing flight, going backwards 

 and forwards over the same ground, and often frequenting one spot for days. Now there 

 is absolutely nothing suggestive of protection in the flight of leonidas, none of that slow 

 sailing movement to show off its coloration, which is so characteristic of the protected 

 Danaine and Acraeine. Moreover, there is no Danaine occurring south of the Zambesi which 

 is anything like it at all, and this is very significant. I cannot therefore resist the conclusion 

 that in this country leonidas is one of those unprotected species which has succeeded in the 

 struggle for existence by its strong and rapid flight, and perhaps by protection in the larval 

 stage, like P. demodocus and P. corinneus. Whereas in Natal, it has found it advantageous, 

 owing to the abundance of Amauris echeria, to adapt its coloration in mimcry of that species 

 by the reduction in size and number of the spots in the fore-wing, and the toning down 

 of the colour from glaucous green to greenish white, accompanied by the marked change 

 in its mode of flight ... I believe in Central Africa it is said to mimic T. peiiverana, 

 and it would be most interesting to find out whether it has there assumed the Danaine 

 flight.' 1 



In this latter connexion Dr. Longstaff states (Trans. Ent. Soc, p. 638, 1908) that he 

 observed P. leonidas flying slowly at the Zambesi Falls, though he did not see T. peiiverana. 

 And Mr. Neave, after collecting in North Rhodesia and the upper region of the Congo, 

 informs me that P. leonidas does, in that region, fly slowly, and in a similar manner to 

 T. peiiverana, which it there accompanies. 



It will be noticed that Mr. Marshall suggests that P. leonidas may be protected in its 

 earlier stages, and it is interesting to note that Trimen states (S. Afr. Butt., 3, p. 216) 

 that the pupa which is suspended on the underside of the leaves is extremely difficult 

 to distinguish, as the outhne and coloration ' all combine to assimilate the pupa to the 

 surrounding foliage in the most deceptive manner '. Brasidas does not appear to have 

 a very wide range, being largely confined to the south of Africa, Cape Colony, Zululand, 



1 The wording of this passage is purely figurative. No one, least of all Mr. Marshall, would suggest that 

 the butterfly could voluntarily change its appearance because it ' found it advantageous ' to do so. 



