( xxvi ) 



both butterflies are equally common, but those forms of 

 Melitaea aurinia, which do not resemble Haniearis lucina are 

 rare or absent, the reason being that they are exterminated 

 by insectivorous birds. It is to be noted that the birds on 

 either side of the Channel are of the same species, and that the 

 passage of the Channel to a bird of ordinary powers of flight 

 is only a matter of a couple of hours. 



We are now in a position to understand more clearly the 

 state of affairs on the Victoria Nyanza. 



What proof does Dr. Carpenter bring forward for his state- 

 ment which I have put in italics ? None whatever ! It is a 

 form of argument familiarly known as begging the question, 

 and in itself is sufficient to condemn the theory, but, as I shall 

 show later, the whole theory of mimicry is founded on this 

 species of argument. 



Prof. Poulton, on what evidence I know not, has stated his 

 belief that each young bird during its tasting experiments 

 only tastes a few of each unpalatable species in its neighbour- 

 hood; this being so, the bird population on the mainland 

 must be very considerable to produce such an effect, and there 

 should not be any great difficulty in making a sufficient number 

 of observations; but it is curious that Dr. Wiggins, a keen 

 entomologist, and one who has resided at Entebbe for some 

 years, knows nothing about it. 



Now the bird population on the mainland and on Bugalla 

 is practically the same, and it cannot be seriously contested 

 that what takes place on the one does not take place on the 

 other, and Dr. Carpenter must agree with me that if it can be 

 shown that the birds on Bugalla do not eat butterflies it is 

 proof positive that they do not eat them on the mainland 

 twenty miles away, and therefore there is no thinning out of 

 transition forms; that their absence is not due to natural 

 selection, and that his case of mimicry falls to the ground. 



Is this evidence forthcoming ? is it trustworthy ? and from 

 whom ? 



I think it will come as a matter of as great a surprise to other 

 Fellows as it did to me when I say it comes from Dr. Carpenter 

 himself ! I must confess that I am amazed that neither he 

 nor Prof. Poulton, who supervised his paper, did not realise 



