21 



Genus THYCA Wllgr. 



This genus is generally called Delias Hb. But Mr. Snellen is of opinion 

 that the systematist need not count with the names given by Hubner, because 

 the diagnoses of this author concerning these names are very incomplete and 

 sometimes even incorrect, so that the animals cannot be recognized by them 

 with certainty. The best rules are, indeed, of no use, when practised without 

 intelligence; this is certainly also the case with the principle of systematical 

 priority which has been admitted now for good reasons, and in the acknowledgment 

 of such names as those given by Hubner, which are not sufficiently justified, 

 Mr. Snellen thinks he sees such an application of this system. This opinion 

 may certainly be defended. I, however, prefer to keep to the names once given 

 which have a claim to being maintained by universal use. 



The Thycas are butterflies that live on trees. The caterpillars of the 4 

 Java species, whose life-histories I have observed, all feed on species of Loranthus ; 

 I noticed the same concerning those of T. Rosenbergii Voll. in Celebes, while 

 Moore and De Niceville mention it also concerning the larva of T. Eucharis 

 Drury which lives in India and in Ceylon, and Rainbow says the same concerning 

 the three species of this genus which occur in Australia. Weale {Trans. EnU 

 Soc. 0/ Lojidon, 1878) mentions the same plant also as the foodplant of some 

 species of Pieris. 



I. Egialea Cram. (PI. II, fig. 2). 



Cramer, II p. 141 //. 189 D, E. 9 {i'j'i<^ Pap. Egialea. 



Ill p. 115 //. 258 A ^. c? (1782) 



BoiSDUVAL, Spec. Gen. //>. 450(1836) Pieris „ 



Snell. v. Voll., Mon. d. Pier. p. 7 (1865) „ 



Staud., Exot. Schm. p. 34 pi. 20 (1884 — 86) Delias „ 



W. J. Common at Batavia (3 — 14), Buitenzorg (265), Sindanglaya (1082) 

 and Soukapoura (70) in the province of Prajangan. 



C. J. Touban on the north-coast. 



E. J.? 



The eyes of the butterfly during life, are of a pale bluish grey. With 

 respect to the black on the upper-side of this species, the same thing may be 

 said as has been mentioned concerning the colour of Pieris Java. Without 

 doubt this species only differs from several other suchlike forms occurring in 

 other islands, in the stage of colour-evolution which they have reached. I do 



