Adapted from Doesburg (1968).
MALE.
Head seen from above fully twice as broad as long, vertical triangle rather coarsely punctate, one and a half times as high as broad basally; eyes at nearest point of approach separated for a distance larger than that between the posterior ocelli, eye-facets but very little enlarged in front; frontal triangle large, inflated, shining black; face one-fourth of the breadth of head, scarcely concave between antennae and tubercle, black, covered by white dust and bearing white pile. Facial tubercle is just visible in profile. Antennae orange, the dorsal half of basoflagellomere somewhat darkened, scape and pedicel very small, basoflagellomere large, inflated, one and a half times as long as high. Arista short, dark brown.
Thorax: Scutum dull, black, the sides and two submedian vittae, greyish, the large postpronotal callosities, the notopleura and the postalar calli, yellow. The suture between the notopleura and mesopleura is rather deep, the transverse suture between the notopleura is less deep but still well visible. Pleura mostly blackish; below the notopleura there is a broad fascia of greyish white, silky dust, nearly reaching the mesocoxae and upwards covering the notopleura. Scutellum tawny with, at the tip, a few short, black, marginal bristly hairs. Metascutum blackish. Legs: Coxae black. Anterior four legs with yellow femora and tibiae, the latter with darkened apex. Metafemora with exactly the basal half yellow, the remainder black with narrow yellow apex. Metatibiae also with the basal half yellow, the other half black. All tarsi black, the metatarsi more or less yellowish. Protarsi shortened and dilated. Wings hyaline, stigma dark brown, elongate; alulae well developed. Calypter white, lower lobe with very short, scanty fringe. Halteres yellowish.
Abdomen slender, three times as long as mesonotum and scutellum together, basally nearly as broad as the scutellum, from there steadily narrowing to the apex of the second segment, then again widening so that the third and fourth segments together form a longish, rather inflated club. Dorsum of abdomen black, posterior margin of all terga, basal two-thirds of second and third terga, and the very large hypopygium, yellow. Sometimes the basal yellow fascia of the second tergite is divided by a darker yellow or brown vitta, that of the third tergum is always divided into two rectangular blocks. Fourth tergum with a subbasal, broad, bent fascia of grey dust on either side, broadly separated medially. Basal three sterna of the venter yellow with a narrow, blackish, medial vitta, fourth sternum blackish. Abdominal pile very short and scanty, except on the fourth tergum where it is well visible, and on the venter where it is fairly long, white.
In 1883 Bigot described Speghina? macropoda after one female from "Birmania". Bigot used to place a question mark after the generic name when he was not sure that the described species did belong to the genus in question. The not forwardly produced oral margin, the presence of a facial tubercle, the spinose hind femora, and the wing-venation created a doubt about the correct use of the name Sphegina. He thought macropoda might need a new genus. De Meijere (1908) erected the new genus Spheginobaccha with Sphegina macropoda Bigot as type-species (from Doesburg 1968).
Synonyms:
Sphegina? macropoda Bigot, 1883: 331.
?Baccha robusta Brunetti, 1908: 50; Hervé Bazin, 1924: 292.
Spheginobaccha macropoda (Bigot, 1884).
Bigot, J. M. F. 1884. Dipteres nouveaux ou peu connus. 22e partie, XXXII: Syrphidi (2e partie). Especes nouvelles, No 1er. Annales de la Société Entomologique de France (6) 3, 315-356. [1884.01.31]
unless otherwise stated