( xv ) 



must be studied ; the opinions of previous writers must be carefully criti- 

 cised, but not slavishly adopted ; and thus works like Lyonnet's wonderful 

 volumes on the Cossus, or Victor Audouin's on the Pyralis of the vine ; and 

 monographs like Kirby's on the British bees, Mr. M'Lachlan's on the 

 Trichoptera, Mr. Eaton's on the Ephemerida, and Mr. Pickard-Cambridge's 

 on the spiders, will be added to our stores of general knowledge. 



When we consider the present state of our knowledge of the vast 

 number of species of insects compared with that of all the other tribes of 

 animals, the young entomologist may well feel appalled at the difficulties 

 which are opened to his view. Thus, whilst Professor Huxley estimates 

 the number of all the known species of animals (exclusive of the Arthro- 

 poda) at 50,000, we find nearly 80,000 species of beetles alone catalogued 

 in Harold and Gemminger's list. Such a number of species unfortunately 

 necessitates the creation of vast numbers of new genera, with the still 

 greater multiplication of subgenera or groups established, often recklessly 

 on insufficient or ill-considered characters, all which is unfortunately 

 forming an almost insuperable barrier against the real progress of the 

 science. How this barrier is to be overcome seems to me to be a matter 

 deserving very serious consideration ; for, whilst it is necessary in the 

 special investigation of any given group to separate discordant species and 

 regard them as separate genera or subgenera, the requirement of the more 

 general student is opposed to such numerous and often arbitrary divisions 

 which it is impossible for him to study, but of which it is useful for him to 

 have some general idea. An instance of this kind is afforded in the last 

 part of the ' Proceedings ' of the Linnean Society, where Mr. W. F. Kirby 

 has established a number of new genera founded upon different thick- 

 thighed species of the older genus Chalcis. The species are for the most 

 part South American, and unique in the British Museum Collection, and. 

 for more general purposes may well be known and spoken of under the old 

 generic name of Chalcis. Fifty years ago, M. Laporle (Comte de Castelnau) 

 partially endeavoured to obviate the difficulty by employing generic names 

 which had evident reference to the principal genus in the group; thus* , we 

 had genera or subgenera Lucidota, Luciola, Lucio, and Lacernuta estab- 

 lished in the family Lampyrida} (Ann. Soc. Ent. Fiance, vol. ii., 1833). 



The same difficulty exists in the elevation of local forms or geographical 

 subspecies to the rank of distinct species without a due consideration of the 

 primitive forms from which they have probably sprung. The consideration 

 of the nature of the differences which distinguish these various forms and 

 the possible cause of their origin deserve the most attentive consideration of 

 the student, although the evidences of their origin may be as difficult to 

 investigate as those on which the varieties of the human race or those of 

 our domestic animals have originated, of which also amongst plants the 

 genera Rosa, Ranunculus, and Salix afford equally difficult examples. Tn 



