500 L. de Niceville & Dr. L. Martin — Butterflies of Sumatra. [No. 3, 



pupa state the imago emerges. Though so weak and slow in flight, 

 they are very clever in avoiding being caught by the net. 



550. Dkrcas gobrias, Hewitson. 



Grose Smith. Wallace. Standi nger. Kirby. Distant. Hagen. 

 Is rather rare, and occurs from Bekantschan to the Central Plateau. 

 Collectors never bring in more than two or three specimens at one time. 

 We have specimens caught from February to August only. 



551. Ixias lddekingii, Vollenhoveu. 



Hagen. Wallace. Kirby. Originally described from a male from 

 the mountainous country in the interior of Sumatra. It is very rare, 

 Dr. Martin has only two males taken in January of the last year of 

 his residence in Sumatra, one caught in the Battak mountains at a high 

 elevation, the other taken near Bohorok near the western boundary of 

 our area, where also Dr. Dohrn's collector obtained several males. 



552. Ixias flavipexnis, Grose Smith. 



I. fluvipennis, Grose Smith, Nat. Wand, in the East. Arch., p. 275 (1885) ; id., 

 Grose Smith and Kirby, Rhop. Ex., p. 2, n. 3, pi. Ixias i, figs. 6, 7, male [nee 

 female] (1888) ; id., Weymer, Stet. Eat. Zeit., vol. liii, p. 121 (1892). 



Thestias fiavipennis, Snellen, Tijd. voor. Ent., vol. xxxiv, p. 335, pi. xvi, figs. ], 

 2, male; 3,4, female (1892). 



Ixias pyritis, Weymer, Stet. Ent. Zeit., vol. xlviii, p. 13, n. 11, pi. i, fig. 4, male 

 (1887;. 



Hagen. Snellen. Originally described from Sumatra where it 

 alone occurs and only at high elevations, from Soengei Batoe to the 

 Central Plateau, and the males are very common on the sandy banks 

 of little streams ; the females, very rare and taken in the forest only, 

 come to hand in the proportion of one to a hundred males. They 

 probably escape capture by the collectors owing to their white colour, 

 being mistaken for the common species of Catophaga and Hiposcritia. 

 Occurs throughout the year, Dr. Martin has specimens taken in every 

 month. Both Drs. Martin and Hagen have obtained it from the Gayoe- 

 and Alas-lands, where the butterfly possibly occurs at a lower elevation 

 than in the Battak mountains. 



553. Catophaga kero, Fabricius. 



Grose Smith. Snellen. Hagen. Wallace. Staudinger. Semper. 

 A very variable species in both sexes. Males from Sumatra have the 

 ground-colour on the uppersidc of both wings " golden-yellow " (Appias 



