X INTRODUCTORY. 



names of our butterflies have not always been quite the same 

 as those now in general use. There has, however, been far 

 less stability in scientific nomenclature, and very many changes 

 in both generic and specific names have been made during the 

 past twenty years, more especially perhaps within the last 

 decade. 



Genera are now founded by some specialists on characters 

 which formerly served to distinguish one species from another, 

 whilst other authorities merge several genera in one upon 

 certain details of structure that are common to them all. 



Patient research into the entomological antiquities has re- 

 vealed much important material, some of which may furnish a 

 new interpretation of the Linnean classification of Lepidoptera. 



The discovery of the earliest Latin specific name bestowed 

 upon an insect, is a labour which entails a large expenditure 

 of time and requires fine judgment. Great credit is therefore 

 due to those who undertake such investigations, the result of 

 which may tend to the establishment of a fixed nomenclature 

 in the, probably not remote, future, although it sadly hampers 

 and perplexes students in the meanwhile. 



All things considered then, it has been deemed advisable 

 not to make many changes in specific names, and to retain the 

 old genera as far as possible. The arrangement of families, 

 genera, etc., will be found to accord with that most generally 

 accepted both in England and on the continent. 



