( xxiii ) 



Instead of a general, really very simple, deduction, let us take 

 an example. 



There are in a certain district two unpalatable species, the 

 one numbering 10,000 individuals, the other 2000. If the 

 foes inhabiting the same district destroy annually 1200 

 individuals of an unpalatable species before learning to avoid 

 it, this number would be lost by each species if they were 

 different; but if they were so similar that the experience 

 with one serves for the other, then the first would lose 1000, 

 the other 200 individuals; the first would thus gain 200, or 

 2 per cent, of its total strength, and the second 1000, or 50 

 per cent, of its total. This consideration shows further, that 

 in all probability in many cases (e. g. Thyridia and Ituna) the 

 question which of the two species is Model, and which is 

 Mimic, is idle : each has reaped some advantage from being 

 like the other ; they may even have gone to meet each other. 



The following paper was read as a basis for a discussion on 

 Mimicry : — 



The Mimetic Theory — " A Crucial Test," by Colonel 

 N. Manders, F.Z.S., F.E.S. — The publication of three papers* 

 on the subject of Mimicry by Dr. Hale Carpenter in our Trans- 

 actions for 1913, brings this subject once more prominently 

 forward, and his whole-hearted enthusiasm as a supporter of 

 it must have given much satisfaction to those who hold the 

 same views as himself. Those, however, who like myself 

 have never been able to accept the theory, but who at the same 

 time admire the persistence and energy with which it is con- 

 stantly brought to our notice in spite of the many rebufis 

 it has lately received, have read with mixed feelings Dr. 

 Carpenter's papers. Personally I have nothing but admira- 

 tion for the amount of most valuable work he has done at odd 

 moments snatched from his official duties, the skill with which 

 he has marshalled his facts, and the courage of his interpreta- 

 tion of them expressed in almost the last paragraph of his first 

 paper (p. 616) : " If, as I believe, this explanation be the correct 



* Pseudacraea eurytus hobleyi, Neave, its form and its models on 

 Bugalla Island, Lake Victoria, with other members of the same com- 

 bination. By G. D. Hale Carpenter, D.M. Oxon. Member of the Royal 

 Society's Sleeping-sickness Commission. 



This is the only paper I deal with. 



