Common Butterflies of Sri Lanka

M
LC
E
Sri Lankan Tree Brown Lethe daretis
Medus Brown Orsotriaena medus
S
LC
Nymphalidae
Male
Female
The outer margin of the hind wing is serrated, forming a short tail at the tornus. Male:
Dark brown on the upper surface with a sub-marginal row of small black spots on the
hind wing and a few yellowish brown patches near the upper margin of the forewing.
The underside is dark brown in colour and clouded with purplish scales. All the ‘eye
spots’ on the hind wing are rounded. There is no marked difference in size between
the ‘eye spots’ on interspace 2 and 6 in relation to the others, while the ‘eye spots’ on
the forewing lack a yellowish outer ring. The forewing has an irregular, oblique white
line beyond the cell. Female: The upper side resembles that of the female Tamil Tree
Brown but the oblique line on its forewing is much more irregular and the row of
sub-marginal spots on its hind wing is outlined in diffused yellow-brown rings. The
underside is similar to that of the male, but the oblique line on the forewing is wider.
The Sri Lankan Tree Brown feeds on tree sap and rotting fruits. It uses the colour
pattern on its underside to camouflage itself against tree trunks with lichens and
moss. Unlike other Tree Browns, it comes out even during day time.
This butterfly is only found in cloud forests in the highest mountains.
LFPs: it has been observed that adults lay eggs on Arundinaria debilis
The sexes are alike except for the sex brand found at the lower margin of the underside
of the forewing in males. The upper side is completely dark brown except for the
two rows of very thin white sub-marginal lines. They are far more prominent on the
hind wing. The underside is dark brown with a broad, regular, oblique white band
across both wings. Its margin is sharp towards the base and diffuses towards the outer
margins. Both its wings have two large ‘eye spots’ each and the hind wing has another
small ‘eye spot’ adjacent to the upper big spot. The blue iridescent rings fade with age,
sometimes vanishing entirely. Sub-marginal lines are present as on the upper surface.
The Medus Brown feeds on tree sap, fruits and other rotting matter found on the
ground. It never climbs to tree tops for sap like the other large Nymphalids. It lives in
the shade under thickets, but comes out to grass patches more frequently than other
Bush Browns. Its flight is slow and it always remains within a small area.
This butterfly is common throughout the country. It does not go deep into forests, but
is found in shady habitats.
LFPs: Axonopus compressus (f.dx ;Kfld,), Oryza sativa (f.dhï), Panicum maximum
(.sks lS/iai).
Nymphalidae
88 Common Butterflies of Sri Lanka
Common Butterflies of Sri Lanka 89