THE SPECIES OF THE GENUS IXO OF LEACK. \) / 



had my«elf the pleasure, by breedinp^ from the eggs, to prove 

 most certainly the identity of Anthocharis Belemia, Esp., 

 and Glance, Hb., and that of Anth. Belia, Esp., and 

 Ausonia, Hb. 



It is much more difficult, however, to prove with con- 

 vincins: certaintv the occurrence of local varieties. The so- 

 called "transitional forms" play here an important part; 

 but they require to be treated with the greatest care, es- 

 pecially when we have only isolated specimens of such tran- 

 sitional forms. It has been proved that distinct species can 

 by their union produce hybrids ; these hybrids stand more or 

 less midway between the two species from which they are 

 descended ; but how incorrectly should we argue from such 

 specimens that the two parents were the same species ! Such 

 individual transitional specimens, which therefore are pos- 

 sibly hybrids, or else only aberrations, prove absolutely 

 nothing to conviction. Then with regard to local varieties, 

 it would be conceded that a form can only be considered as 

 a local variety, when it does not occur in the same locality 

 with the typical form (just as we cannot repute a form a 

 variety of time if it occurs simultaneously with the other 

 form, nor can we call a form an aberration if it occurs in 

 great numbers). Hence, if we know positively of any form 

 that it occurs along with the allied form in plenty at the 

 same time and at the same place, it is imperatively necessary 

 to consider both forms as distinct species. This, for example, 

 is the case with Epinephele Nurag, Ghil., and Epin. var. 

 Hispulla, Hiib., both of which I took by hundreds in com- 

 pany in the island of Sardinia, and where it is a matter of 

 indifference, that amongst thi'ee or four hundred of Epine- 

 phele Nurag, I took one single specimen, which stands pre- 

 cisely midway between the two species. Also in Granada I 

 was first cured of my earlier false notions that Mhodocera 



1864. H 



