Rhoga Walker Figs 327-331

Rhoga Walker, 1857: 157. Type species: Rhoga lutescens Walker, 1857: 157, by monotypy.

Papiliomyia Hull, 1937a: 27. Type species: Papiliomyia sepulchrasilva Hull, 1937: 28, by original designation. For synonymy see Hull (1949).

Description.

Body length: 5-10 mm. Stingless bee mimicking flies with short to moderately long antennae and oval, kite-shaped or more or less parallel-sided abdomen. Head slightly wider than thorax. Face convex; narrower than an eye. Lateral oral margins not produced. Vertex narrow, convexly produced and shining in most species, flat in some. Occiput wide and parallel-sided over entire length. Eye with short, sparse pile. Eye margins in male not converging at level of frons, with mutual distance 2 to 3 times as large as width of antennal fossa. Antennal fossa about as wide as high. Antenna as long as or shorter than distance between antennal fossa and anterior oral margin; basoflagellomere shorter to longer than scape, oval; bare. Postpronotum pilose. Scutellum semicircular, in some species weakly sulcate apicomedially; without calcars. Anepisternum without sulcus; pilose anterodorsally and posteriorly, widely bare in between. Anepimeron entirely pilose. Katepimeron convex; bare. Metapleurae either separated or forming postmetacoxal bridge. Wing: vein R4+5 without posterior appendix; vein M1 perpendicular to vein R4+5; postero-apical corner of cell r4+5 rectangular, with small appendix; crossvein r-m located within 1/4 of cell dm, usually within basal 1/10. Abdomen oval or kite-shaped, 1.5 to 2.5 times as long as wide. Tergites 3 and 4 fused. Sternite 1 pilose or bare. Male genitalia: phallus furcate near apex, with dorsal and ventral process equally long; epandrium without ventrolateral ridge.

Diagnosis.

Vein R4+5 without posterior appendix. Occiput widened and parallel-sided over entire length.

Discussion.

In some species (e.g. Rhoga mellea (Curran, 1940), Rhoga maculata (Shannon, 1927)) the metapleura are separated and do not form a postmetacoxal bridge. So far in Microdontinae, this character state was known only in the genus Spheginobaccha (Cheng and Thompson 2008).

The type specimen of the type species, Rhoga lutescens Walker, 1857, is not present in the BMNH-collection (pers. comm. N. Wyatt), where it is supposed to be according to Thompson et al. (1976) and Thompson (2010). Apparently it is lost.

Diversity and distribution.

Described species: 5. Central and South America. Several undescribed species are known to the first author.