THE ENTOMOLOGIST. 



Vol. XVIL] MAY, 1884. [No. 252. 



VARIATION OF EUROPEAN LEPIDOPTERA.* 



By W. F. de Vismes Kane, M.A., M.R.IA. 



The Author defined a species to be a group similar among 

 themselves throughout their life-history and sexual development, 

 with a common inherited characteristic difference in some stage 

 of their development from all other groups of individuals. 

 " Types," he said, " can thus be fixed on of sufficient per- 

 manence to render of great interest all records of their variation, 

 since such records will in many cases eventually constitute the 

 history of fresh species." It was such alterations of charac- 

 teristics, giving birth to incipient species, that he intended to 

 consider. 



He then pointed out that there were apparently two controlling 

 forces at work among living organisms, — namely, the law of per- 

 sistence and the law of variation, — and that the naturalist was met 

 at the threshold of his investigations by the problem of whether 

 the variations ever exceed the limits of species so that one type 

 merges by imperceptible gradations into another ; and if this be 

 answered in the affirmative, he has then to consider " whether 

 generic distinction form inexorable limits to variation." There 

 are certain groups of Lepidoptera which challenge retrospective 

 enquiry into their past history, such as the Hesperiidse, and 

 especially the genus Syrichthus, of which there were about 

 sixteen admitted European species, all so closely approximate 

 that their synonymy is almost in a chaotic condition, alveolus 



* Abstract of a paper read before a Meeting of the Yorksbire Naturalists' Union 

 at Barnsley, Mareb 4th, 1884. 



ENTOM. — MAY, 1884. O 



