354 Mr. G. A. K. Marshall on 



Proc. 1897, pp. xx-xxxii, xxxiv-xlvii). The following 

 extracts from a letter indicate the line Mr. Marshall would 

 have taken had he been in England at the time. — E. B. P.] 



Malvern, Natal ; Oct. 7, 1897. — I ani much struck with 

 the large amount of adverse criticism levelled against the 

 theory of even Batesian mimicry. The theory of converg- 

 ence (Miillerian mimicry) might perhaj)S be considered as 

 debatable, but how any one wlio has paid any attention 

 to the subject can doubt the reality of Batesian mimicr}', 

 I cannot understand, and the attempt to explain it away 

 by climatic causes seems to me weak in the extreme. If 

 the view, advocated by many, that birds cannot be reckoned 

 among the principal enemies of butterflies in their imago 

 state, be true, then I consider that we may practically 

 abandon the whole theory of mimicry as at present applied 

 to the Acrminie and Banain/u of South Africa at all 

 events, for from what I have observed of these insects I 

 am convinced that their warning coloration cannot have 

 reference to either mantises, Asilidx, or lizards, which are 

 practically the only other enemies that can be taken into 

 account. Moreover, the swift flight of the majority of 

 edible species can only have been developed to enable 

 them to escape from winged enemies, and that this de- 

 velopment is due to AsilidsB or dragon-flies is more than 

 I can believe. Certainly the paucity of records of birds 

 eating butterflies is somewhat disconcerting, but this is 

 doubtless due to the fact that not sufficient attention has 

 been paid to the subject, which would entail long and 

 patient observation of the birds themselves, an occupation 

 that the average entomologist is not likely to indulge in 

 when out collecting. Personally I do not suppose I have 

 seen such an occurrence more than perhaps half-a-dozen 

 times ; the birds being the Paradise flycatcher {Taysi- 

 'plione perspicillata), the bee-eater {Merops apiastcr), and 

 two rollers (Coracias spatulata and Eurystomus afcr) ; but 

 then I admit that I have paid little or no attention to 

 the matter until quite recently. 



The habits of the Teracoli, especially in their winter 

 forms, liave always seemed to me strongly suggestive of 

 their being frequently attacked by birds. With hardly an 

 excej)tion they are fah'ly swift fliers (especially the 

 "purple -tips"), keeping comparatively close to the ground 

 and dotlging well. If struck at gently as they fly by, 

 they dodge and hurry onwards but still continue their 



