63 



viduals has become very dark, almost black; it cannot be stated definitely 

 whether this difference is due to the increase of black or to the subsequent 

 fading process. It is, however, clear that we have to deal here, not with the 

 result of directly operating influences, but with an evolutional mutation process; 

 in low lying districts as much as in mountainous regions, in the wet season as 

 well as at the height of the dry season, light and dark coloured specimens 

 are equally met with. 



Specific distinctions, based purely on some difference in form of wing, as 

 adopted by Bingham, I am unable to admit; Cyllo Leda L., for instance, 

 clearly teaches us that when a species is in a state of active evolutional change 

 this manifests itself in the form of wing as much as in the colouring; for the 

 same reason the form of wing in some species, such as Danais Agleoides 

 Felder, differs in the two sexes /. e. when they have reached different stao-es 

 m the evolution of form. As regards the specific differences which Bingham 

 and Fruhstorfer infer from the secondary sexual characters in males, I am 

 not inclined to attach much value to this either. Moreover, Bingham is himself 

 still doubtful in this respect, while Fruhstorfer observes that these characters 

 are extremely variable in the genus Debts, even in the seasonal forms of the 

 same species and the forms which he regards as subspecies. 



The form or colour of such secondary characters cannot be considered of 

 the same weight as attaches to the sexual organs proper. Much accurate 

 investigation of ample material from different districts and especially much 

 pedigree breeding are, indeed, required before the acceptance of .specific 

 differences on these grounds may be considered justifiable. 



I. Nala Felder. (PI. XVII, fig. 51^, 51^, 51^, 51^^). 



Feeder, Wien, Ent. Mon., p. 403, No. 46 (1859) . . . Mycalesis Nala. 

 Novara, Le/>., p. 500, No. 868, //. 57, fig. 10 



^'867) ," . . „ Sudra. 



Fruhstorfer, (Seitz, Grosssclwi. d. Erdc), pi. 936*5 (191 1). 



W. J. Tjibodas (14 10); Megamendoung mountains (1480); Salak mountains 

 (780); mountains in the prov. Prayangan (1500); mount Tjerymay, prov. 

 Cheribon. 



C. J. Oungaran (800) {Jacobson); Magelang (500). 



E. J. Tosari (1777); prov. Banyouwangy, Tengger mountains (1200) 

 iyjacobson). 



Feeder, who discovered the species, subsequently described a variety from 



17 



