Somena similis Moore
 1858-9, Cat. lepid. Insects Mus. E. Ind. Co. 2: 351.
1883, Lep. Ceylon, 2: 87, syn. n.
1949, Ann. Mag. nat. Hist. (12), 1: 706, syn. n.
Holloway, 1976: 47.
Diagnosis. The facies of the male forewing is distinctive, with the yellow border
irregular with two slight protrusions of the reddish brown zone into it
centrally and subcostally. The female resembles various Orvasca species,
but can be distinguished (in Borneo at least) by the weakness or absence of a
third, apical yellow patch on the forewing margin.
Taxonomic notes. The synonymy above is based on examination of relevant type material.
The typical race has grey hindwings in the female, but ssp. irrorata stat. n. from the Indian Subregion has them yellow.
The species is often confused with the Indian type species, but the
latter has a broader yellow forewing border in the male, with correspondingly
longer brown protrusions into it. The female of scintillans also has
deeper yellow patches on the forewing margin, including a strong one at the
apex. The valves of the male genitalia are slightly deeper and shorter than in scintillans;
in the female genitalia the ductus and bursa are smaller, less robust. A
further species of the complex, S. moorei Snellen comb. n., occurs
in Sulawesi, with facies much as in scintillans but with more robust
genitalia that have the valves deeper and shorter still, and the saccus is
Schintlmeister (1994: 133) referred to the secondary homonymy of Artaxa
similis Moore with Phalaena similis Fuessly if both are placed in Euproctis.
This is not relevant for the generic placement here, though, in the event,
the replacement name cannot be Artaxa limbata Butler as suggested by
Schintlmeister, as this was originally described as, and represents, a distinct
taxon (see comment under Orvasca bicolor Heylaerts). The
secondary homonymy of the name irrorata Moore in Euproctis ceases
with recognition of Somena, as the older use of this epithet is for the
Javan Orvasca irrorata Moore comb. n., originally described in Euproctis.
Hence the replacement name raratior Collenette becomes unnecessary
for ssp. irrorata.
The identity of Trichia exigua Nietner from Sri Lanka (see
generic synonymy) is unclear but it is probably a species in this complex,
possibly a senior synonym of irrorata. The original description is not
precise enough to determine this, and no type material has been located (see
also Moore (1883)).
Schintlmeister (1994) identified this species as scintillans and
illustrated its genitalia in his fig 109, though he referred fig 108 to scintillans.
Geographical range. Indian Subregion to Sundaland.
Habitat preference. The species is frequent in a wide range of primary
forest types and also in disturbed areas, secondary forest and plantation. It
has been recorded less frequently at altitude but occurs to as high as 1670m (Bukit
Biology. See the generic account. Kalshoven (1981) described an Indonesian larva
attributed to scintillans as having a red dorsal band and several lateral
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