LXI 



natural selection, neither of which, however, is scientifically established ; the old 

 assertion that the fact of some butterflies being distasteful to birds constitutes 

 an argument in favour of the theory of mimicry, he also considers as practi- 

 cally proved. Yet this has in reality been long since sufficiently refuted. In 

 conclusion he declares the observations thus adduced to aeree well with his 

 " facts " quoted supra and he professes to demonstrate that they receive strong 

 support from these " facts " . We may, however, quite well leave out of account 

 what Dr. Dixey adduces in this connection since neither his " facts " nor the 

 observations in question have any scientific value. This applies equally to the 

 whole of his lecture, which is characterized as much by a lack of precise 

 logical arrangement as by a complete absence of the requisite critical faculty. 

 The theory of mimicry — like any speculative doctrine whatever — does not 

 lend itself to demonstration by means of a mass of ill-digested observations. Now 

 what cannot be proved adequately may at the utmost be acknowledged by 

 science as hypothesis but even this must rest on a sound basis. When any 

 phenomenon cannot be explained in any other manner a conjecture so soundly 

 based and, therefore, very admissible may in this respect pass muster as 

 hypothesis. As soon, however, as any other equally admissible solution presents 

 itself such hypothesis falls to the ground. 



On the same day Prof. E. B. Poulton gave an account of Dr. C. A. 

 Wiggin's Researches on Mimicry in the Forest Butterflies of Uganda (1909). 

 These observations have reference to the joint occurrence ot some species or 

 forms of the Acraeine Genus Planema with butterflies belonging to other 

 genera, which at the same places strongly resemble one another, from which 

 fact various considerations concerning the existence of mimicry are deduced. 

 But in all these cases it is assumed a priori that the butterflies in question 

 represent models and mimics respectively ; this should, however, be proved first 

 for until this has been done these observations are without foundation. No 

 attempt, however, is made to establish this proof. Only from a confused 

 mental process the idea can arise that these resemblances, in themselves, however 

 remarkable they may be, have of necessity been produced by mimetic action. 

 From these alone this conclusion can never be drawn. Prof. Poultox, there- 

 fore, has likewise failed to adduce any proof of the theory of mimicry on 

 this occasion. 



Mr. J. K. Jordan, also on the same day, discussed " The systematics of 

 certain Lepidoptera ivhich resemble each other, and their bearing on general 

 questions of evolution " . 



