A LIST OF INDIAN BUTTERFLIES. 557 



i-espects, they are races of the same species : also no two local races 

 can fly together. This latter statement was not accepted by Col. 

 Bingham, who, for instance, placed Y'pthvma ceylonica as a race 

 of huhneri, in spite of the fact that they fly together and that, as 

 had been pointed out by Elwes, their male organs differ. Dr., 

 C'hapman also considers that Gyaniris huegeli and ccelestina are 

 conspecific, though flying together, as their male organs are alike : 

 of course, this may be a case of dimorphism and the question can 

 only be settled by breeding experiments. 



There is at the present time a tendency to multiply local races, 

 and the difficulty is to know where to stop : often in mountainous 

 districts, forms from neighbouring valleys differ and a change of 

 elevation may produce a marked eff'ect. Where sufficient material 

 has been available in the B. M., I have carefully investigated the 

 merits of every local race described up to the time of writing : 

 where there was no visible difference to be detected the race has 

 been sunk as a synonym. 



A species or race is subject to variation in a number of ways as 

 follows : — 



''a) Seasonal forms due to climatic changes during the year. 

 In some species the differences are very small, in others as 

 JSrebia annada there is a sharply marked change, while in 

 others again as Terias hecahe, though the extreme forms are 

 very different, yet intermediate forms connect them by an 

 almost insensible gradation. To name seasonal forms, as done 

 by Seitz, seems a mistake : it would be better to designate 

 them as d. s. f. and w. s. f. (dry or wet season form) or f. vern. 

 and f. aest. (spring or summer form). 

 (V>) Dimorphs ocour in a few species being oftener confined to 

 the female sex. True dimorphs are frequently occurring forms 

 unconnected to the normal forms by intermediates. They are 

 best designated by a Latin name with the prefix " d " and 

 also " (5" " or " 5 " if confined to a particular sex. 

 (g) Varieties are forms frequently occurring with the normal 

 form, differing from it , in certain particulars, but connected 

 by intermediates. What varieties should be named is a 

 standing casus belli among entomologists. With highly 



