500 L. de Niceville & Dr. L. Martin — Butterflies of Sumatra. [No. 3, 
pupa Btate the imago emerges. Though so weak and slow in flight, 
they are very clever in avoiding being caught by the net. 
550. Dercas gobrias, Hewitson. 
Grose Smith. Wallace. Staudinger. 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 ludekingii, Vollenhoven. 
Hagen. Wallace. Kirby. Originally described from a male from 
the mountainous country in the interior of Sumatra. It is very rare, 
Dr. Martin bas 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 flavipennis, Grose Smith. 
I. jlavipennis, 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. Ent. Zeit., vol. liii, p. 121 (1892). 
Thestias Jiavipennis, Snellen, Tijd. voor. Ent., vol. xxxiv, p. 335, pi. xvi, figs. 1, 
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 obtaiued it from the Gayoe- 
and Alas-lands, where the butterfly possibly occurs at a lower elevation 
than in the Battak mountains. 
553. Catophaga hero, Fabricius. 
Grose Smith. Snellen. Hagen. Wallace. Staudinger. Semper. 
A very variable species in both sexes. Males from Sumatra have the 
ground-colour on the upperside of both wings “ golden-yellow ” (Appias 
