362 L. de Niceville & Dr. L. Martin— Butterflies of Sumatra. [No. 3, 
As mentioned above, north-eastern Sumatra does not possess a 
well-marked dry- and wet-season, such as is found over most of the 
continent of India, there being no month in the year when it does not 
rain ; indeed it is rare for a week to pass without a shower, consequently 
there are no dry-season forms of butterflies to be found in Sumatra except 
the dry-season form of ^lelanitis ismene, Cramer ( = leda, Linnaeus, aucto * 
rum ), which, as also in Java, is found all the year round equally commonly 
with the wet-season ocellated form, M. determinata , Butler. 
We would especially bring to notice the occurrence in North- 
Eastern Sumatra of a very peculiar endemic form of the female of Pupilio 
onemnon , Linnaeus. It belongs to the first form group of females of 
the species, i.e ., the form which has no tail to the hindwing and is 
most like the male ; the second form is also tailless, but has a large 
white patch on the outer half of the hindwing never found in the 
first form. This peculiar first form female has the “ epaulettes ” (i.e., 
the basal portion of the discoidal cell of the forewing on both surfaces) 
almost pure white, faintly tinged only with oclireous, so that it may 
perhaps be called cream-coloured. It probably mimics the second form 
female of Papilio forbesi , Grose Smith, which also possesses similar 
white epaulettes, the first form lacking them altogether, and is 
therefore like the male. It may be urged against this theory that 
females of P. forbesi are very rare, especially the wliite-epauletted 
second form, Dr. Martin having obtained only two specimens of it. 
But this scarcity is probably more apparent than real, both sexes of 
P. forbesi occurring in equal numbers, but the males coming down to 
the hill streams to drink are caught in large numbers, while their less 
thirsty spouses keep only to the thick forest where they escape the 
dangers of the butterfly net. 
It should be pointed out that de Niceville is solely responsible for 
the nomenclature employed in this paper, and for all statements ap¬ 
pearing in the first person singular, together with the descriptions of 
species and sexes ; while Martin, who has lived for 13 years in north¬ 
east Sumatra, is mainly responsible for the notes on distribution in the 
island itself, scarcity or rarity, season of occurrence, &c., of the 
various species ; de Niceville having but twice visited Sumatra, and 
then only for short periods. 
The literature of the subject is of course very scattered and frag¬ 
mentary. The following is a list of the principal papers dealing with 
the Rhopalocera of Sumatra : — 
I. P. C. T. Snellen. Tijd. voor Ent., vol. xx, p. 65 (1877), “ Le- 
pidoptera op Sumatra verzameld, voornamelijk in Atcliin.” Enumer¬ 
ates 35 species. 
