THE ATHALIA GROUP OF THE GENUS MELIT^EA. 383 



from another, but where the species are so ill-defined as in the 

 present group, it appears to me not unreasonable to suppose 

 that this may be the case ; yet it is with the utmost diffidence 

 that I hazard the suggestion of the following table, in which 

 doubtless there are many " missing links," and which fails to 

 account satisfactorily for the origin of the cinxia group, which is 

 almost certainly, however, the most modern of the three : — 



Ancestral form (possibly asteria or merope). 



I I. 



merope. asteria. 



I i. 



I varia. 



I 



(? iduna). 

 I 



I 



I I aurinia. parthenie. 



cynthia. maturna. | 



{? trivia), deione. athaha = auroiia. 



dictynna. 

 (?) dictynnoides. 



britomartis. 



Such a table as this does not of course attempt to give, or 

 even to hint at, the periods at which the evolution of different 

 species began in comparison with each other ; for instance, 

 although I think it possible, and even probable, that deione and 

 athalia had a common origin in parthenie, yet I have no doubt 

 that the former is a vastly older form than the latter ; the 

 suggestion indeed that partlienic is an older form than athalia, 

 still more that it is the direct ancestor of the latter, needs expla- 

 nation. Athalia then is the most unsettled form of all in this 

 group, and compares only with aurinia in this respect in the 

 elder, though it is exceeded by pha'hc and didyma in the younger 

 group. There are, in fact, scarcely two locahties in which this 

 species is quite alike, and in all probability it will split up in the 

 course of ages into many species, some of which will no doubt 

 persist while others will become extinct. It is the extreme want 

 of fixity in this species that first suggested to me the probability 

 of its comparatively modern origin ; its connection with parthenie 

 is obvious, but it is equally obvious that the connection of 

 parthenie with the exclusively high-level (and therefore ancestral) 

 form varia is closer than that of athalia with the same species, 

 which is a further hint that the latter is the less ancient of the 

 two. It may be fairly replied that such a position is incon- 

 sistent with my view that the more southern are the later forms, 

 since parthenie is to be found further south than athalia. If, 



