Key to the species of Bizarrifrons

1 Tergal plates not entirely pigmented (as in Figs 5–6); sparse tergal chaetotaxy in both sexes (as in Figs 9–10, 18, 24–25).......................................................................................... magus group … 2

1’ Tergal plates entirely pigmented (as in Figs 7–8); dense tergal chaetotaxy in both sexes (as in Figs 33–34, 40–41)............................................................................................. picturatus group … 7

2 Female subgenital plate distally narrow (see Fig. 3 h in Eichler, 1938: 234)................................. B. clayae

2’ Female subgenital plate distally broad (as in Fig. 15).......................................................... 3

3 Conus at most reaching the first antennal segment (scape) (Fig. 11).............................................. 4

3’ Conus surpassing the first antennal segment................................................................. 6

4 Frons markedly asymmetric (as in Figs 9–10, 24–25)......................................................... 5

4’ Frons slightly asymmetric (Figs 18 and 21).................................................. B. latifrons sp. nov.

5 Males: tergites VII with <6 setae on each side (including the inner and outer posterior setae, but not the postspiracular and its accessory); tergite VIII with <8 posterior setae on each side; tergites IX+X broad; subgenital plate without transversal fenes- trae. Females: tergite IX+X entirely brown.......................................................... B. magus

5’ Males: tergites VII with ≥ 6 setae on each side; tergite VIII with ≥ 8 posterior setae on each side; tergites IX+X thin; subgenital plate with transversal fenestrae. Females: tergite IX+X largely white........................... B. wecksteini sp. nov.

6 Male genitalia with large and broad callus on the posterior and lateral margins of the mesomeral complex (see Fig. 2 b in Eichler, 1938: 230)............................................................................. B. francisi

6’ Male genitalia with large and broad callus only on the posterior margin of the mesomeral complex (see Fig. 2 c in Eichler, 1938: 230)............................................................................ B. meinertzhageni

7 Frons slightly asymmetric (Figs 40–41); male subgenital plate with transversal fenestrae (Figs 20–23)................................................................................................ B. quasisymmetricus sp. nov.

7’ Frons markedly asymmetric (Figs 33–34); male subgenital plate without fenestrae (as in Fig. 14)..................... 8

8 Male genitalia with large and broad callus on the posterior margin of the mesomeral complex (as in Fig. 37)... B. picturatus

8’ Male genitalia with small and narrow callus on the posterior margin of the mesomeral complex (see Fig. 47 in Carriker & Díaz-Ungría, 1961: 45)........................................................................ B. juruani