Asiobaccha bimaculata (Keiser, 1952) comb. nov.

(Figure 5a, b, e)

Baccha bimaculata Keiser, 1952: 161 . Holotype: ♀, NMB. Type locality: Indonesia: Langgai . Baccha (Allobaccha) bimaculata of Knutson et al. 1975: 321.

Differential diagnosis

Dark species with yellow face and scutellum (Figure 5a, e), with broad alula, and infuscated wing, which is bare basally (including basal part of cell R) (Figure 5b). It has a well-defined mesonotal collar, and the metatarsus is bicolourous (Figure 5a). The most similar species is A. nubilipennis, but A. bimaculata differs from it by having tergum 3 black with two medial subtriangular yellow maculae, pointing anteriorly and not reaching lateral margins ( A. nubilipennis has a complete yellow fascia on tergum 3) and the colour of the pleural pollinosity (golden in bimaculata and white-yellow in nubilipennis). Another characteristic to separate both species is the colouration of the metafemur; A. bimaculata has the metafemur dark brown with a yellow apex, while A. nubilipennis has a yellow metafemur with a medial dark annulus.

Variation. A paler specimen has metafemur yellow very basally and apically.

Length (N = 4). Body, 12.7 – 14.0 (13.2) mm; wing, 10.5 – 12.7 (11.3) mm.

Geographical distribution

Species known from Sumba Island.

Type locality

Indonesia: East Nusa Tenggara Province, Pulau Sumba, Sumba Tengah (Central Sumba Regency, Langgai, 10°03’S, 120°28ʹ E.

Material examined

Type material. Holotype, female, deposited in the Naturhistorisches Museum (Basel, Austria) and labelled: ‘ TYPUS ’ [red] ‘C.- SUMBA // Langgai // 16.7.1949 // Expedition // Bühler-Sutter ’, ‘ HOLOTYPE // Asiobaccha // bimaculata // (Keiser) // det. X. Mengual 20 14’ [red] (specimen photographed). Paratypes: ‘ PARA- // TYPUS ’, ‘C.- SUMBA // Langgaliru // 5.10.1949 // Expedition // Bühler-Sutter ’, ‘ PARATYPE // Asiobaccha // bimaculata // det. X. Mengual 20 14’ [yellow] [1♀, NMB]; ‘ PARA- // TYPUS ’, ‘O.- SUMBA // Lalukku // 7.7.1949 // Expedition // Bühler-Sutter ’, ‘ PARATYPE // Asiobaccha // bimaculata // det. X. Mengual 20 14’ [yellow] [1♀, NMB].

Nontype material. INDONESIA: East Nusa Tenggara Prov., Sumba, near Lewapaku, km 57 on Waingapu to Waikobubak road, 9 – 12 December 1985, J.D. Weintraub [1♀, USNM, USNMENT 00890789] .