Semidonta nigribasis Hampson stat. n.

Hyperaeschrella dentata insulicola Kiriakoff, 1967: 60; 1968: 202.

Diagnosis

The forewing patterning is very similar to that of Hexafrenum species but there is no subtornal pale patch and the subapical one is brown rather than cream. The male genitalia are very different, the uncus being entire, the valve consisting of three components, and the transtillae bearing dorsal lobes. The aedeagus has no apical processes but the tube with deciduous stellate spicules in the vesica is much more highly developed than in Hexafrenum.

Taxonomic Notes

• The species is allied to H.kosemponica Strand (Taiwan) stat. rev., being very similar in forewing markings and colour, but with blunt, straight rather than acute, curved dorsal processes to the valves of the male genitalia, a more produced bifid process to the eighth tergite and, in the female, a signum like an almost complete ring, deep-sided, rather than a thin, slightly angled band of sclerotisation. The species nigribasis Hampson (N. E. Himalaya) and dentata Hampson (Sri Lanka) have the forewings shades of grey rather than indigo, and a more evenly curved (concave basad) ante-medial.
• Schintlmeister & Lourens (2010) placed Hyperaeschrella as a synonym of Semidonta Staudinger (type species biloba Oberthür, E. Siberia). Schintlmeister (1994b: 229) placed insulicola and dentata Hampson (but (S & P) not kosemponica Strand) as synonyms of nigribasis Hampson, as he detected no differences in the male genitalia. Facies differences were noted in Part 4, but it appears that there can be great external variability in this, as Schintlmeister also placed the Sumatran hollowayi Bender as a synonym of producta Kiriakoff. The hollowayi form has not yet been recorded for Borneo, but material is limited. However, S & P recorded producta but not the hollowayi form for Thailand, and were unsure whether hollowayi was a form of producta or a separate taxon. Species of this group occur further east in the Philippines (familiaris Schintlmeister (1993), sororcula Schintlmeister & Lourens (2010)) and Sulawesi (occidentalis Schintlmeister (1993)).

Geographical range

Sundaland, ?India (2 ♀♀ in BMNH).

Habitat preference

The species has been taken infrequently in a variety of lowland forest types.

Biology

The species has been reared from Nephelium lappaceum (Sapindaceae) in Malaysia (CIE Records: Dr K.C. Khoo).

The larva, here described from photographs kindly sent by Dr Khoo Khay-Chong (Universiti Pertanian Malaysia), is cylindrical, the abdominal end curving smoothly down to the anal claspers. The head and ventral surface are light leaf-green, the head with a narrow black lateral stripe. The spiracles are picked out with black, the most posterior one with a much larger black area than the rest and those on the segments with prolegs are somewhat less definite. The spiracles are set in the dorsal part of a moderate white lateral band which runs down to the anal claspers and is edged finely with red dorsally. Above this lateral band is an ochreous green band of similar width. The dorsal surface is paler green extending to, and darkening at, a narrow, pale yellow dorsolateral line on each side. There is a diffuse, narrow, somewhat broken, dark greenish dorsal line which becomes more intense on the last segment of the abdomen. Copies of the photographs of larva and pupa have been deposited in the BMNH.

Genitalia: