( xxviii ) 



Noctuid moth about two inches in expanse." It is obvious, 

 therefore, that if butterflies formed any portion of these birds' 

 food except the smallest they would have been detected. 



Now what holds good for Bugalla must also hold good for 

 the country twenty miles away, and so by Dr. Carpenter's 

 own showing the birds on the mainland do not eat butterflies, 

 and he has no justification for his words which I have placed 

 in italics. 



There is not a particle of evidence, therefore, to show that 

 the absence of intermediates is due to natural selection, but 

 strong evidence that it is not. 



A theory may be regarded as reasonably true or used as a 

 good working hypothesis, even if there is little or no direct 

 evidence of the truth of its premises, if it fits in with the results 

 of observation and experiment, and until evidence to the 

 contrary is forthcoming; when this is produced it should be 

 discarded. 



The theory both of Bates and particularly that of Miiller 

 rests mainly on two unproved but reasonable propositions : 

 that certain genera of butterflies are distasteful, and that 

 young birds undertake tasting experiments. If sufficient 

 evidence has been published to disprove both propositions 

 or to throw reasonable doubt on them, it is clearly the duty of 

 the supporters of the theory to lay it aside until they have 

 disproved or explained the rebutting evidence. But Mimicrists 

 do not do this ; they ignore or pay but slight heed to adverse 

 evidence and pursue their way apparently oblivious of it. 



Theoretical deductions from so-called instances of mimicry 

 do not advance their views, but rather converts neutrality 

 into active hostility. 



We may inquire what direct evidence of distastefulness and 

 tasting experiments has been brought forward by supporters 

 of these theories who have resided in Africa, and who have 

 published papers similar to those of Dr. Carpenter. 



From East Africa the Eev. St. Aubyn Kogers, who has 

 spent some years in that part of the country, has brought none. 

 Dr. Lamborn, a most acute observer on the West Coast, none. 

 or less than half a dozen instances of distastefulness. 



In South Africa, Mr. Marshall fourteen observations in 



