CXXll 



The death is also announced of L. Bedel, of Paris, one of the 

 best contemporary French Coleopterists, and of two very- 

 successful collectors of Lepidoptera in the tropics, H. Fruh- 

 storfer, who died at Munich, and A. H. Fassl, who has been 

 carried away by the vicissitudes of the climate of the Amazons. 



I will now address you 



On some Aspects of Variation in Lepidoptera, 



Looking back in m-ind on the exhibits and discussions during 

 the two years I have had the honour of occupying the presi- 

 dential chair of the Entomological Society of London, I think 

 I am right in saying that two subjects have claimed much of 

 our attention and interest : (1) the dissimilarity among the 

 individuals of Lepidoptera which constitute a species — or 

 variation, and (2) the similarity obtaining between many 

 different species — or mimetic resemblance. The two subjects 

 are so closely interwoven that one cannot deal with the one 

 without touching upon the other. We are all familiar with 

 the fact that the variation of a species is a two-fold one : we 

 observe on the one hand the diSerences^ between the individuals 

 of a species within a faunistic district — or synpatric variation, 

 and on the other hand the differences which are perceived if 

 the whole range of the species is taken into account — or 

 dyspatric variation. Although for you, who have studied 

 variation in one group of insects or the other and have seen 

 at the meetings the exhibits bearing on the subject, there will 

 hardly be anything new in what I have to say on the variation 

 of Lepidoptera, the two-fold aspect of variation is very little 

 understood outside the circle of active systematists and field- 

 biologists. While the publications on systematics consist to 

 a large extent of the differentiation between the geographically 

 separated races of species, in the works of philosophers explain- 

 ing the world to us scarcely any notice is taken of this side of 

 variation — or it is impatiently waved aside, as for instance by 

 the famous philosopher Nietzsche, who, in a chapter against the 

 Darwinian explanation of evolution, says about the modi- 

 fications through the influence of food and climate that " they 

 are in reality absolutely negligible." You will agree with me, 

 I know, that in these circumstances it is a duty of biologists to 



