Rhoga are small, delicate, pale yellowish flies, with distinct black pilose brushes on the metatibia. The head shape is also characteristic with the occiput being of uniform development, as wide dorsally as ventrally in lateral view (Cheng and Thompson 2008).
Rhoga sepulchrasilva differs from Rhoga maculata (Shannon) in the possession of only a single basal wing macula; apical half of thorax largely yellow, with two round maculae and a wedge shaped macula; posterior half with two L-shaped maculae. Abdomen past second segment almost wholly dark. Yellow wing border extended across wing as a vitta (Hull 1937).
Rhoga species are small, pale orange to yellow flies that have antenna long, scape much longer than basoflagellomere; occiput uniform, as wide dorsally as ventrally; metatibia narrow, with long pile; abdomen elongate, parallel-sided; postpronotum and anpisternum pilose; vein R4+5 without appendix; vein M without appendix; face without a tubercle; and vein M1 straight or slightly recessive.
Rhoga sepulchrasilva (Hull, 1937).
Hull, F.M. (1937) New species of exotic syrphid flies. Psyche 44, 12-32, pl. 2.
This species was originally described as genotype of the new genus Papiliomyia (Hull 1937), as Papiliomyia sepulchrasilva. Later, Hull (1949) placed it under Rhoga Walker.
Adapted from original description (Hull 1937).
Weakly chitinized, delicate species, that suggest moths or scorpion flies.
Head hemiglobular in profile, occiput above tumid and vertex protruding as a conspicuous bump, but otherwise the front and vertex are quite narrow. Ocelli situated at top of the protuberance. Antennae situated near top of head, the scape quite elongate, in fact being considerably longer than remaining two together. Arista weak and delicate. Face narrower from the front, converging from below the antennae. Eyes bare. Gena practically absent. The enormous eyes seem to cover almost the whole head.
Thorax: Scutum exceedingly conspicuous and deep. Scutellum without points. Legs: Metafemora slender, basally spindled. Metatibiae thickened apically and with a deep shallow groove separating the apical fifth. Metatibiae very brushy as in Trigonoid bees. Wings long and slender. Vein R4+5 without appendix. Vein M1 straight and recurrent as well. Postical cross vein (=CuA1) sigmoid in the genotype species. Costa deeply beaded with setigerous tubercles. Wings banded in both the known species.
Abdomen elongate, over two times as long as wide. Widest at junction of second and third segments, but very little wider here. Fourth segment most deeply transversely concaved as far as the anterior two-thirds, leaving a convex rim posteriorly. The concave portion most oddly covered with centrally converging, flat lying hair from the base and sides.
unless otherwise stated