BIRDS AND BUTTERFLIES 243 



He has had the courage to take up the cudgels 

 and reply to Mr. Banta in Nature. The reason of 

 this unusual course appears to be that Mr. C. F. M. 

 Swynnerton has made some observations in South 

 Africa which Professor Poulton considers are in favour 

 of his pet theory. 



According to the Professor, Mr. Swynnerton, as 

 the result of three and a half years' investigation 

 in South-East Rhodesia, " has obtained the records 

 of nearly 800 attacks made by 35 species of birds 

 belonging to 30 genera and 18 famiUes, upon 79 species 

 of butterflies belonging to 9 famiUes or sub-families." 



Professor Poulton does not seem to see that the 

 researches of Mr. Swynnerton are altogether sub- 

 versive of the theory of protective mimicry. In 

 order that natural selection may totally change the 

 colouring of a butterfly (as it does according to the 

 theory of protective mimicry), that butterfly must 

 be habitually preyed upon by large numbers of birds, 

 which must be so vigilantly and unceasingly on the 

 look-out for it, that its only chance of escaping from 

 their attacks must be for it to assume a disguise. 



Compare with this the state of affairs revealed 

 by Mr. Swynnerton's observations. He worked 

 for three and a half years, and, as his investigations 

 extended to eighteen families of birds, they must have 

 been very extensive. Exactly how extensive they 

 have been we do not know, because he has not yet 

 published them. Nevertheless, as the result of three 

 and a half years' watching and stomach examination 

 he has evidence of only " nearly 800 " attacks made 



