Common Butterflies of Sri Lanka

Sri Lankan Tree Nymph Idea iasonia
Blue Glassy Tiger Ideopsis similis
L VU E
M VU
Nymphalidae
The sexes are alike, but there is great variation in pattern and size among individuals. It
has narrow, elongated, but blunt tipped forewings. Both wings are silvery white with
black veins and black patches throughout on both sides. Its abdomen is white with a
broad black dorsal line.
The most distinct habit of the Sri Lankan Tree Nymph is its slow, floating flight among
trees at higher levels. This butterfly is seen to even casually fly among flocks of birds,
since it is unpalatable to them. Several males go after a single female in their courtship
displays in this floating flight, which is a gorgeous spectacle to behold. During these
flights, males extrude yellow-coloured hair pencils from the backs of their abdomens
that are capable of emitting a scent to attract females. This species never engages in
mud puddling.
This is a forest-loving species and is usually seen around bodies of water such as
streams and ponds. Its usual distribution is confined to the forests of the wet zone, up
to the lower highlands and intermediate zone. Some historical records show that it
has also been observed in the dry zone.
The sexes are alike. The background colour on the upper surface of its wings is black,
while the underside is brown. The markings on its forewing are blue, while those on
its hind wing are glass white. The differences in these colours are prominent on the
underside. These markings are similar in shape on both the upper and lower surfaces.
Its forewing cell has a basal streak and a large spot distally. Three other lines radiate
from the base of the forewing with one thin line above the cell and two broad lines
below.
The Blue Glassy Tiger has a moderately fast, casual flight. It prefers to fly about 5 feet
above the ground but readily comes down to the long panicled flowers of herbaceous
plants for nectar. When they settle on these flowers, they adopt a hang-up position
since the panicle cannot withstand their weight. They go to higher levels for basking
and roosting.
This butterfly can be commonly seen in both forests and verdant home gardens,
but its distribution is restricted to the western parts of the country ranging from
Negombo to Matara.
Nymphalidae
LFPs: Its sole LFP is Parsonsia alboflavesscens (j,a w.=K).
LFPs: Larvae have been successfully reared only on Tylophora indica
58 Common Butterflies of Sri Lanka
Common Butterflies of Sri Lanka 59