semialba Walker comb. n.
Thalera semialba Walker, 1861, List Specimens lepid. Insects
Colln Br. Mus. 22: 601.
Chloromachia semialba viridior Prout,
1916, Novit. zool. 23: 204.
Diagnosis. The half white, half green nature of both wings is diagnostic,
together with the more or less straight boundary between the two on the hindwing.
On the underside there is a conspicuous submarginal black spot centrally.
Taxonomic notes. E.
semialba has the valves of the male genitalia rather ovate, with a long,
blunt process at the base of the valve costa that bears long spines towards the
apex. In the Sri Lankan subspecies it is more acute, tapering, sinuous. To the
east there occurs a trio of species with the valves more rectangular and the
costal process much shorter, lobed distally: E. vicaria Herbulot comb. n.
(Palawan); E. lepta West comb. n. (Luzon); E. angiportus Prout
comb. n. (Sulawesi). The costal process shows a range of variation in Himalayan,
Thai and Burmese material, also noted by Dr K. Yazaki who has sent the author
photographs, including one of a Sumatran male with a long, sinuous process.
Apart from this, Sundanian specimens examined have been relatively consistent in
the form of this structure.
Geographical range. N.E. Himalaya, Burma, Sundaland; Sri Lanka (ssp. viridior)
Habitat preference. This is primarily a lowland forest species, and was taken
particularly frequently in heath forest at 15m at Telisai in Brunei. One
specimen was taken at 1618m on Bukit Retak.
Biology. Moore (1884-7) illustrated the larva with the typical dorsolateral
flanges, but these are most prominent on the central 3rd and 4th abdominal
segments, shorter elsewhere. The colour is olive green, speckled brown, the
anterior and posterior segments more pale purplish brown. There is a double
brown line dorsally. The pupa is green, thickly and minutely speckled with
The host-plant is Loranthus
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