Key to species of Borgmeiermyia

1. Median lateral scutellar setae long, at least 2/3 length of posterior lateral scutellar setae ............................................................................................. 2

– Median lateral scutellar setae short, about one-half length of posterior lateral scutellar setae (sometimes slightly longer than one-half) ............................ 3

2. Male cercus and surstylus broad and cercus strongly curved dorsally at mid length in lateral view and with apex rounded (Figure 2) (Colombia, Peru, Brazil)............................................................................................. peruana

– Male cercus and surstylus less broad (not as above) and cercus slightly curved dorsally in lateral view and with apex truncated (Brazil, Paraguay) ............... ............................................................................................... paraguayana

3. Vein R 4+5 setulose dorsally between half and the whole distance to r-m crossvein, but not beyond r-m; male with outer rami of flagellomere brown and the inner rami yellow; wing costal margin with a brown continuous macula from apex of Sc to apex of R 2+3 (Figure 5) (Brazil)........................ brasiliana

– Vein R 4+5 setulose dorsally far beyond r-m crossvein; male with inner and outer rami of flagellomere brown; wing costal margin with a brown macula from apex of Sc to apex of R 2+3 but this macula partially interrupted after apex of R 1 (Figure 7) (Brazil).............................................................. rozeni