1895.] L. de Niceville & Dr. L. Martin —Butterflies of Sumatra. 495 
It is treated by Trimen as a purely African butterfly. The original 
figure does not at all agree with the original figure of T. drona, Hors- 
field = T. libythea , Fabricius, as it has no black border to the hindwing 
on the upperside. Watson in Journ. Bomb. Nat. Hist. Soc., vol. viii, 
p. 515 (1894) says that T. drona as identified in the British Museum has 
the “ marginal band of hindwing evenly narrow throughout.” This is 
incorrect, as a glance at the original figure will show, at the costa it is 
broad, fining away to nothing at the anal angle. Butler states in 
Ann. and Mag. of Nat. Hist., fifth series, vol. xvii, p. 221 (1886) that 
the unique specimen described by Horsfield is a female. I doubt 
this, I should say it was a male, as it is clear yellow on the upperside; 
were it a female it would have a heavy sprinkling throughout of black 
dots. It therefore agrees in this character with T. libythea , which is 
defined by Watson as having the “marginal band of hind wing broad 
at apex and narrow at anal angle.” Butler in Cat. Fab. Lep. B. M., 
p. 227, says that T. libythea is “an unspotted variety of Horsfield’s 
T. drona.” From a careful examination of my series of Terias of this 
group, it appears to me that T. libythea (following the identification 
of this species in the British Museum) is the dry-season form, with 
T. rubella , Wallace, as a synonym, and T. drona the wet-season form, 
with T. senna , Felder, as a synonym, of one and the same species. 
The wet-season form ( T. drona ) alone occurs in Sumatra. In Sumatra 
it is found only on the Central Plateau of Tobah and Karo, and even 
there is not very numerous and occurs only at certain times. Though 
the collectors were instructed always to catch this species when they 
could, they only brought in specimens in December and January, when 
it appears to be common, and in May and July, when it appears to be 
rare, and not a single one in any other month, so the species in 
Sumatra would appear to be double-brooded. 
539. Terias tilaha, Horsfield. 
Hagen. Sumatran specimens have a reniform mark at the end, 
and a W-shaped mark at the middle of the discoidal cell of the forewing 
on the underside. The female is paler on both surfaces than the male, 
of a lighter more gamboge-yellow colour, with the marginal band on 
the upperside of the hindwing twice as broad, narrow at the apex, very 
broad at the anal angle, and extending on to the disc on either side of 
the submedian nervure. It is the rarest Terias of our area, found 
throughout the year on the outer mountains and also in the plains, as 
several specimens have been obtained at Selesseh, though Dr. Hagen 
says that it is not found below an elevation of 500 feet. In 1887 Dr. 
Martin took a specimen at the Terdjoen Estate very near the sea. It 
