64 



also live on a lot of other plants, partly mentioned already. The same thing 

 we have already observed with respect to the difference between Callidryas 

 ScYLLA L. and C. Pomona F., two closely related species that have evidently 

 arisen from the same original form, and in which exactly the same relics of 

 pigment appear on the under-side as in the above mentioned species of Terias. 

 Of the former, a species which varies little even as imago, I only saw uniform 

 caterpillars, always living on the same plant; but of the other species, whose 

 imago occurs in many different forms caused by the process of colour-evolution, 

 the caterpillars also differ much in colour and live not only on the plant on 

 which the other species occurs and which perhaps therefore has already been 

 the foodplant of the original form, but also on several other plants. For this 

 reason I suppose that the change from a monophagous way of living of the 

 caterpillars into a polyphagous manner of life, which has been caused by par- 

 ticular circumstances, may have been the cause in the two above-mentioned 

 cases of the rise of a specific difference between butterflies of the same species 

 according as some have undergone during the larval state that change in their 

 manner of living and others have not. 



6. Tilaha Horsf. 



HoRSFiELD, Cat. Lep. ^. /. C /. 136 (1828) Terias Tilaha. 



BoiSDUVAL, Spec. Gen. I p. 668 (1836) „ „ . 



Snell. v. Voll., Mon. d. Pier. /. 65 (1865) „ „ . 



Distant, Rhop. Mai. p. 303 //. 25 fig. 8 (1882 — 86) ... 



This butterfly seems to me not to be common in Java ; Dr. Martin 

 mentions the same about Sumatra. I only received it from the province of 

 Prajangan in W. J.. Namely from Soukapoura (65) and from the south-coast 

 from the districts near the Tjiletoe or Sandbay. Fruhstorfer, however, found 

 the species common in the mountains along the south-coast of E. J.. Early 

 stages unknown. 



Genus NEPHERONIA Butl. 



I take this genus to be an Indo-Australian form of the African genus 

 Eronia Hb. in which a strong increase of the black has taken place, which 

 has, however, only followed the veins of the wings, while on the parts of the 

 wings between these, the process of growing paler continued in the meantime 

 in its different stadia from red into yellow and white. Just the same pheno- 

 menon has occurred among many Indo-Australian Danaidae, which differ also 

 from the African species of this family by this process of colour-evolution, so 



