( xxii ) 



that the larvae of the hybernating flies had probably bred in 

 a large heap of decaying grass and weeds in the yard outside 

 the part of the building with the cistern-loft in its roof. 



The first statement (1878) of Mulleriax Mimicry. — 

 Prof. PouLTON said that during a recent study of Fritz Miillers 

 work he had come across an earlier statement than the classical 

 paper " Ituna and Thyridia : a remarkable case of Mimicry 

 in Butterflies," published in Kosrnos (May 1879), translated 

 by Prof. Meldola, F.R.S., and printed in the Proceedings of 

 the Entomological Society of London for the same year 

 (p. xx). This brief preliminary account of the hypothesis 

 was of interest in many ways, and as it appeared to have 

 escaped the attention of naturalists, Prof. Poulton thought 

 that the Entomological Society would wish to publish the 

 following translation kindly prepared by Mr. E. A. Elliott from 

 the original in Zool. Anzciger (Carus), I, (1878). pp. 54, 55 : — 



On the advantages of Mimicry among Butterflies. 

 By Fritz Muller, Itajahy, Brazil. 



It is remarkable how one sometimes puzzles for years over 

 questions the solution of which is so simple that one can 

 hardly understand how there could have been even a momentary 

 difficulty over them. 



This was my experience in the matter of Mimicry among 

 Lepidoptera. Danainae, Ithonmnae, Acraeivae, Heliconinae, 

 all appear to be equally well protected by disagreeable smell 

 and taste, and yet there are among them a number of mimick- 

 ing species. The smell of the species of Eueides is especially 

 strong, yet Eueides pavana is a mimic of Acraea ihalia, E. 

 Isabella of Helic. eucrafe, or Mechanitis lysimnia, and E. 

 aliphera resembles Colaenis jidia, except in size. What ad- 

 vantage can it be to a creature protected by repellant odour 

 to resemble another similarly protected species ? If their 

 foes avoid protected species by " instinct," none at all; but 

 if, on the contrary, as appears so much more probable, the 

 foes have to learn their unpalatability by experience, then the 

 benefit is all the greater, the less numerous the species. The 

 advantage gained by two unpalatable species by their re- 

 semblance is in inverse ratio to the square of their numbers. 



