Milionia borneensis Inoue

Milionia fulgida Vollenhoven, 1863, Tijdschr. Ent. 6 :133.

Milionia fulgida ab. reducta Gaede, 1914, Int. Ent. Zeitschr. 7: 353.

Milionia fulgida reducta Gaede; Holloway, 1976: 84.

Diagnosis

This is the largest Bornean species, distinguished by lack of any orange marking on the hindwing.

Taxonomic Notes

The Bornean race reducta Gaede is larger than the typical Javan one, with the iridescence on the hindwing deep bluish rather than greenish blue. In the genitalia the digitate process on the valve is more robust in reducta, the ventral group of spines on the sacculus more numerous, and the aedeagus lacks the cornutus, present in typical **fulgida. The species may belong to a group that lacks banding on the hindwing but with a strong orange band on the forewing. The digitate process by the valve costa is seen also in the New Guinea species M. diva Rothschild and M. aroensis Rothschild but these lack spines on the saccular area. In the Himalayan M. pulchrinervis Felder the digitate process is absent but the saccular area is more as in fulgida with a homologous group of spines in the basal position.

M. philippinensis Rothschild (Luzon) has similar facies but no digitate process and only a single group of spines at the interior of a rather broad saccular sclerotisation.

Inoue (1999a) discussed homonymy in the use of the epithet reducta in Milionia, and considered that reducta Gaede, 1914, as applied to Bornean populations referred to fulgida Snellen van Vollenhoven, was infrasubspecific and only validated by Prout, 1932, and therefore preoccupied by reducta Rothschild, 1926. He therefore named the Bornean population ssp. borneensis Inoue. This was raised to specific rank by Inoue & Stüning (2003) when investigating the precise identity of fulgida. M. fulgida is now known from Java, with sspp. baliensis Inoue in Bali and sumbawana Inoue in Sumbawa. A related species, amethystea Inoue, occurs in Palawan, hence this complex may prove also to be present in Borneo. The male genitalia of fulgida have valves ornamented as in the basalis complex. M. borneensis is part of another species group defined on valve ornamentation that contains M. hollowayi Inoue & Stüning (Java), M. stueningi Inoue (Java), M. sommereri Inoue (Sumatra), and M. costidepressa Inoue (Philippines). Similar valve ornamentation is seen in a trio of species with turquoise fasciation from Sulawesi: M. cuneiformis Inoue, M. delicatula Inoue and M. everetti Rothschild.

Geographical Range

Java, Borneo.

Habitat Preference

On G. Kinabalu all specimens were taken at the Power Station locality, at 1930m, during the 1965 survey. On G. Mulu the species was abundant at 1790m in upper montane forest dominated by the conifer Dacrydium. The only other record is from 1680m on Bukit Pagon, Brunei.

Biology

The species comes to light at night but has not been observed flying by day.

Genitalia: