49G ME. W. F. KTEBY ON THE GENERIC NOMENCLATUBE 



G. "When synonymous genera have been described in tlie same 

 year, the current name should be preferred, on the score of con- 

 venience, unless the exact dates can be proved. 



But the application of even these rules would cause great 

 confusion, as we shall soon see. 



I now propose critically to examine the principal genera of 

 Diurnal Lepidoptera established up to 1816. 



Tbe foundation of our modern systems is, of course, the last 

 edition of Linnseus's ' Systema. Naturae,' published in 1707. 



The latest Linnean division of the butterflies was as follows : — 



Papilio Eqiies Trojanus. Papilio Nymphalis gemmatus. 



Achivus phaleratus. 



Ileliconius. Plebeius ruricolus. 



■ • ' Danaus candidus. ■ urbicolus. 



festivus. 



I use the singular form instead of the plural here, because 

 Linnseus himself used both ; and all the principal Linnean sec- 

 tions, except Eques (for which Papilio is retained) and Pleleius, 

 are still used in the singular as generic names. Tabricius uses 

 the plural only. There is little doubt that Linnajus and his 

 immediate followers regarded Eques, Ileliconius, Danaus, Nym- 

 phalis, and Pleheius as ultimate genera ; and Eaper actually 

 employs several of tbem almost as generic names. Fabricius, 

 however, apparently treated them merely as sections, as he did 

 not adopt any of them as generic in his 'Systema Glossatorum.' 



In 1777 Scopoli published his ' Introductio ad Historiam Na- 

 turalem,' in which he divided the Linnean genus JPapilio into 

 Argyreus, Argus, Pterourus, Pattus, Graphium, and Ascia. It is 

 not possible to retain any of these genera. The last, charac- 

 terized thus, " AlsB absque ocellis, maculis, lineis, punctis et 

 Cauda," contains Gratasgi, Napi, Sinapis, Monuste, and Phereclus 

 of Linnajus ; but when we find the remaining species of Picris 

 described by Linnaeus distributed among Pattus and Graphium, 

 on account of the character of their markings, we cannot retain 

 even Ascia, but must agree with Latreille and all subsequent 

 authors in rejecting all Scopoli's genera of butterflies. Argus 

 is retained by some authors for the small blue butterflies ; but 

 Papilio argtis, Linn., which is naturally supposed to be Scopoli's 

 type, is placed by him in his genus Argyreus, on account of the 

 metallic spots on the under-surface of the wings. The genus 

 Argus is thus characterized — "Alse alicubi ocellatse, non can- 



