6o 



f. i. that gave rise to the Blanda Bsd., variety which simply consists of those 

 specimens in which the evolutional increase of the black on the upper-side of 

 the fore-wings in that peculiar way in which it takes place in this species and 

 perhaps generally in the genus Terias Swains, has advanced still far less than in 

 most specimens of the same species. 



In the evolutionary colour process on the under-side, the same thing may be 

 observed as also draws attention in Iphias Glaucippe L., but appearing there on 

 the upper-side viz. that the colour which is disappearing seems to keep longest 

 near the apex of the forewings, where it seems to be concentrated and can be 

 retained a long time. Thus we see that the above-mentioned brown spots on 

 the under-side of T. Hecabe L. have often increased especially near the apex of 

 the wing much more than anywhere else, nay, sometimes even to such an extent 

 that lepidopterologists, who ignore this process, doubt whether there is a specific 

 difference between this species and T. Sari Horsf., which latter species has also 

 arisen from the same ground form as T. Hecabe L. In T. Sari Horsf., 

 however, this spot takes up the whole apex of the wing, in T. Hecabe L. it is 

 sometimes entirely wanting or occurs in a very insignificant degree as a first 

 beginning, but it sometimes also gets rather large, though never so large as in 

 T. Sari Horsf. and never forming a united spot which touches the terminal 

 margin as well as the costal one, as is the case in this latter species. 



The colour and the form of these spots, as well as the place where 

 they are found, the inequality of their occurrence and also the difference of 

 colour and shade between the numerous species of this genus, may easily be 

 explained in this way by a knowledge of the colour- evolution process, but 

 remain an insoluble mystery without this knowledge. In consequence of these 

 differences Moore f. i. in his Lepidoptera of Ceylon enumerates many species 

 of Terias, as is also the case with C. Pomona F. ; so does De Niceville, 

 and in this way about fifty species have gradually been distinguished which 

 must all be brought back, however, to T. Hecabe L. This is also the case 

 with the so-called species T. Silhetana Wall. In the afore-said description of 

 the Rhopalocera of Sumatra by De Niceville and Dr. Martin this form is 

 also mentioned of Sumatra, while as characteristics of difference is given 

 that in T. Hecabe L. there never should occur more than two dark streaks 

 or spots in the discoidal cell on the under-side of the fore-wing, in addition 

 to the reniform spot on the disco-cellular nervules; in T. Silhetana Wall, 

 three and in T. Sari Horsf. only one. But this is without any foundation, 

 perhaps a result of studying a too limited material. I possess Hecabes with three 

 and also Saris with two such spots, and even Hecabe's without any spot at 

 all. These streaks or spots are simply relics of pigment, which occur sometimes 



