Borgmeiermyia Townsend, 1935

Borgmeiermyia Townsend 1935: 292 (genus description, description of type species, key to multifissicorn genera), type species: Borgmeiermyia brasiliana Townsend, by original designation.

Borgmeiermyia: Townsend 1936: 168 (key to Frontinini genera); Townsend 1940: 315 (generic diagnosis); Arnaud 1963: 2 (genus revision, description of B. rozeni and B. peruana, identification key); Guimarães 1971: 166 (cat., Siphonini); O’Hara 1989: 16 (comments); Sehnal 1998: 349 (description of B. paraguayana).

Diagnosis. Small flies, from 4 to 5.5 mm. Colour blackish, with golden and silvery pruinosity. Head: fronto-orbital plate, parafacialia and gena usually golden pruinose; eye with extremely fine, short, sparse hairs (considered bare); male flagellomere multifissicorn, split into about 20 pubescent rami on inner and outer sides of a median rib; female flagellomere elongate and non-ramate; one or two pairs of proclinate frontoorbital setae and one pair of reclinate fronto-orbital setae; facial ridge with erect supravibrissal setae, increasing in length and thickness from above to below, not reaching aristal base. Thorax: mesonotum black in ground colour with golden pruinosity; pleural areas brown to dark-brown with golden pruinosity above and silvery to golden pruinose bellow; scutellum with one pair of basal, three pairs of lateral, one pair of apical and one pair of discal setae; apical scutellar setae much shorter than posterior lateral setae; wing with R1 dorsally setulose, R 4+5 dorsally setulose from base to half-way or beyond r-m crossvein. Abdomen: black with narrow silvery to golden pruinose bands on tergites 3, 4 and 5; tergites 1+2, 3 and 4 with lateral marginal setae; tergites 2, 3, 4 and 5 with 2 or 3 hairlike marginal setae.

Discussion. The systematic position of this genus is uncertain. It was placed within the siphonines by Guimarães (1971) and shares the following features with members of this tribe: wing with R 4+5 dorsally setulose and posterior lateral scutellar setae convergent. Some few siphonine taxa present a modification on male first flagellomere under three diverse conditions: bilobed, trilobed or pectinate (=multifissicorn) (O’Hara 1989). The pectinate condition is also very rare among the siphonines, shared by Borgmeiermyia and some species of Peribaea Robineau-Desvoidy. Borgmeiermyia can also be distinguished from other siphonines by the presence of three pairs of lateral scutellar setae.