25 



at least are never so strongly developed as in the Java specimens, showing 

 thus only a somewhat stronger development of the black at that spot, a 

 phenomenon which appears also in the Java butterflies on other parts of the 

 wings. The specimens of this species from Bali, which are also separated 

 geographically from those of Java, do not differ from these at all. All the 

 forms of Java often occur beside each other in the same districts. It is only 

 a matter of individual differences caused by a more or less advanced stage in 

 the colour-evolution, and which are sometimes found in some region or other 

 in larger numbers than in another, but always mixed and pairing with each 

 other. ') There is no reason whatever for accepting some local influence in 

 this; yet it seemed to me that the rather numerous, very small specimens were 

 principally found in the mountains, especially in the Tengger mountains in E. J., 

 where, beside these, occur, however, also those of a normal size. 



The species is limited to Java, Sumatra and Bali, but only from Java are 

 the above mentioned considerable differences in coloration known. Very nearly 

 related are specially T. Descombesi Bsd., which occurs on the continent of 

 India as well as in Malacca, but also in Lombock, Soumbawa and Flores, and 

 besides T. Zebuda Hew. from North Celebes and T. Eumolpe Grose Smith 

 from Borneo. The original colour was probably red, which colour at present 

 only survives in an oval vermilion streak near the costa on the underside 

 of the hind-wings. In many other species of Thyca such relics of colour 

 are also found; strongest of all in T. Aruna Bsd., a butterfly, which has on 

 its wings relics of all the different colours, appearing in the process of the 

 colour-evolution and which shows at the same time a strong development of 

 the black. The upper-side of the c/ is nearly the same as that of the oldest 

 preserved (f form of T. Belisama, which has been discerned as Belisar or 

 AuRANTiA. In the other species just mentioned, which are closely related to 

 T. Belisama, one sees exactly the same vermilion relic spot as in this one; 

 we may, therefore, suppose that the development of all those out of the same 

 original form did not take place until the red had already disappeared as the 

 general colour, and that for this reason this spot had remained as a relic on 

 that part of the wing, and such in the peculiar form which answered the causes 

 unknown to us, which prevent just in that place the normal contination of the 

 process of colour-evolution from red into orange or yellow. Such a thing may 

 take place on different parts of the wings where, in this way, persistent spots 

 of the former general colour may be preserved a long time. On certain parts 



') So at Aden Yerbury found the typical Danais Chrysippus L. and the fi)rm Dorippus 

 Klug., both such evolutional forms of the same butterfly as are meant here, in coitu. 



4 



