SOME AFRICAN BUTTERFLIES 621 



English fens, has a very closely allied relative, equally restricted 

 in its range, in Central Europe, so the local forms of West 

 Africa have intimate allies in South and East. 



A very striking feature of the Ethiopian butterflies is the 

 large number of species which take part in that mimicry which 

 has such great bearing on the form and colour of species. 

 This is accounted for by the abundance of the two families of 

 Danaidce and Acrceidce, almost totally absent from the 

 Palaearctic region, which are notorious for the possession of 

 powerful scent-glands which render them distasteful to birds. 

 These protected species have been the cause of the most as- 

 tounding modifications of colouring and even of form among 

 butterflies of totally different families, this modification being 

 rendered even more remarkable by the fact that often it is con- 

 fined to the female. This is, of course, plausibly accounted 

 for by the fact that the survival of the female is more important 

 than that of the male. After pairing has taken place — often 

 within a few hours of emergence from the pupa — nature has no 

 further use for the males, but, in order to deposit her eggs to 

 advantage, the female is obliged to stay on the wing much 

 longer and to take many risks which are not necessary previous 

 to pairing. The extreme of this necessity can be well seen in 

 the case of the familiar Vanessa butterflies, such as the Common 

 Tortoiseshell, which leaves the pupa in August or earlier. 

 Pairing takes place almost immediately, but the eggs are not 

 deposited until the following spring, so that for the remainder 

 of the autumn and the long winter the female must manage 

 to survive, if her progeny are to get a fair start in life. Nothing 

 could more effectively explain why this modification of form 

 is so often confined to the female, extraordinary though it 

 appears at first sight. 



II 



In attempting to give some idea of the general character of 

 African butterflies, I can scarcely do better than commence 

 with these protected families, or, as many lepidopterists prefer 

 to call them, subfamilies, Danaince and Acrceince, The 

 Acrceince are entirely unknown in the Palaearctic, only a few 

 species are found in the Indo-Malayan, and one genus only is 

 native to Tropical America. The Danaince are not so exclusive. 

 One species, indeed, the Limnas chrysippus, has a very wide 

 range. It is one of the commonest of butterflies throughout 

 Africa, is found plentifully in Southern Asia, and less commonly 

 in Greece. Several others are found in the South of Asia and 

 are, indeed, only less widely distributed there than in Africa. 



The nearest relatives to these groups which are familiar to 



