The Bionomics of South African Insects. 503 



above, are contained in the following quotations from his 

 letters. 



" Malvern, Natal; Feb. 21, 1897. — As regards the Euralias 

 my experience of them is somewhat limited, but from what 

 I have seen of them I feel pretty sure that their C(>loration 

 is due to mimicry and not to convergence. Their range 

 seems in all cases to agree with that of the Amauris they 

 resemble. In Durban A. ochlea is by far the scarcest of 

 the three, and its mimics B. deceptor and Psciulacr^a ex- 

 •pansa are also very rare ; further up the East Coast, how- 

 ever (Delagoa Bay and Beira), ochlea becomes one of the 

 commonest of the genus, and the two other species are 

 likewise much more numerous. At this place, it is true, 

 Euralia ivahlbergi is certainly more plentiful than A. 

 doniinicanus, but they are both uncommon, and all the 

 specimens we see are practically visitors from the thick 

 bush along the immediate coastline. (This is six miles 



inland.) " 



***** 



" I may mention that in the last few years Mr. Ball has 

 caught two Euralia wahlhergi [in the Karkloof Forest 

 twenty miles N. of Maritzburg], but has never seen 

 Amauris domi^iicanics." 



" Umlcomaas Mouth, Natal; Sept. 8, 1897.— With regard 

 to the Euralia, etc., I must admit that I have never been 

 fully convinced by the contention that in Batesiau mimicry 

 the mimetic species must of necessity be a feeble one and 

 very few in numbers. It seems to me that it would be quite 

 reasonable to suppose that such a mimic might well equal 

 or even exceed in numbers the protected species, though 

 this would of course depend entirely upon the degree of 

 inedibility of the latter. For example, in the case of 

 Euralict mimct and Amauris echeria (probably the best- 

 protected butterfly here), supposing they occur in equal 

 numbers in a giv^en area, and that certain birds by chancing 

 to catch three or four of the former in succession were 

 induced to prey upon butterflies with that coloration, 

 then, from a mathematical standpoint, every alternate 

 specimen caught by any bird would be A. echeria. Now 

 I think we are quite safe in assuming that the fact that 

 every other butterfly caught had a nauseating taste 

 and smell would be far and away more likely to create 

 a strong and lasting impression upon .a bird's mind 

 than the fact that every second one proved to be edible. 



