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Arctornis perfecta Walker comb. n.  
Redoa perfecta Walker, 1862, J. Linn. Soc. (Zool.), 6:128.
Kanchia gigantea Aurivillius, 1894, Ent. Tidskr. 15 (2): 175.

Arctornis perfecta

Arctornis perfecta


This is the largest satiny white species and lacks a discal spot. The forewings are rather acute apically. The other large species are more creamy in colour, more translucent, and have a black discal dot. The frons has a brown bar between the antennal bases, a pair of brown patches immediately below this, and the tips of the palps are brown, slightly more extensive ventrally. The tibiae of all legs have a central brown band. The probable female is much larger, more translucent. The male genitalia have the uncus bilobed. The valves are weakly bifid apically, with a small, setose triangular subcostal flap at about two-thirds. They are deep, the harpe slender, sabre-like.

Taxonomic notes. This species and the Himalayan A. lactea Moore comb. n. (also Peninsular Malaysia, and noted for Sumatra by Schintlmeister (1994)) are very similar in the facies of both sexes, including the ornamentation of the head and legs. In both species the forewing venation has R2 running closely parallel to Rs, anastomosing with it briefly between the branching point of R5 and the splitting of R3 and R4. The association of the sexes in both taxa also requires confirmation from rearing: females appear to be much commoner in lactea and males in perfecta.

Type material of lactea consists of a male syntype in Museum für Naturkunde, Humboldt Universität, Berlin, and a female syntype in BMNH. Females (Figs 378, 386) have rather shallow, triangular ovipositor lobes, a horseshoe-shaped lamella antevaginalis and a boomerang-shaped lamella postvaginalis. A single Bornean female that is probably perfecta resembles that of lactea and the holotype of gigantea Aurivillius (Java; Javan males have genitalia as in perfecta (slides 697, 698)) externally. The abdomen of the gigantea holotype was partly disintegrated, but the genitalia were sufficiently complete to indicate a similarity to the Bornean female and, less so, to that of lactea. The lamella antevaginalis is smaller, less distinctly horseshoe-shaped, and the boomerang-shaped sclerite is less well developed. Similar females occur in New Guinea and Australia, but the genitalia in the former locality resemble those of lactea. Males have not been located.

The male genitalia of lactea are very different from those of perfecta: the uncus is tongue-like; the valve is trapezoid, with a small tongue-like projection at the dorsal angle, and strong extension to the ventral angle, with the distal margin between the angles concave, more strongly so towards the anterior; the harpe is more robust, partially enclosed by a large flap from the valve costa; the aedeagus is half the length of that of perfecta, without a pair of lateral processes.

Geographical range. Sundaland, Sulawesi (slide 2211).

Habitat preference. Most records are from lowland forest, including heath forest and mangrove, but a few specimens have been taken in montane forests as high as 1600m (Bukit Pagon and Bukit Retak in Brunei).

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