Key to the species of Brachystethus

1. Metasternal carina, in profile, strongly elevated anteriorly.....................................................2 Metasternal carina, in profile, flat or little elevated anteriorly................................................ 7

2. Pronotum with a yellowish sub-callous border....................................................................... 3 Pronotum without a yellowish sub-callous border..................................................................5

3. Venter with longitudinal series of yellowish spots. Fourth antennal segment medially swollen.. ........................................................................................................... B. cribrus (Fabricius)

Venter uniformly castaneous to dark-castaneous, lacking yellowish spots. Fourth antennal segment cylindrical............................................................................................................ 4

4. Lobes of dorsal rim of pygophore projected, well developed (fig. 22). Posterior borders of gonocoxites 8 sinuate, not projected over laterotergites 8 (fig. 63)...................................... ......................................................................................................... B. improvisus Breddin

Lobes of dorsal rim of pygophore scarcely projected (fig. 23). Posterior borders the gonocoxites 8 projected in acute angle, over laterotergites 8 (fig. 64)........................ B. vicinus Signoret

5. Hemelytra with a small yellowish callus, near and entad to apex of radial vein............................ ............................................................................................................... B. schuhi, sp. nov.

Hemelytra without callus........................................................................................................ 6

6. Apex of femora and base of tibiae yellowish.................................................... B. signoreti Stål

Legs uniformly castaneous to black.................................................. B. rubromaculatus Dallas

7. Ostiolar rugae short, extending for 1/3 the distance between inner margin ostiolum and lateral margin of metapleura. Metasternum carina with a medial, transversal sulcus................... 8

Ostiolar rugae long, extending for 2/3 of distance between inner margin of ostiolum and lateral margin of metapleura. Metasternal carina lacking sulcus.................................................... 9

8. Dorsal surface black, with red spots on hemelytra, in variable extension (fig.8).......................... ................................................................................................................ B. tricolor Bolívar

Dorsal surface black, with yellow spots on hemelytra, in variable extension (fig. 9)................... .............................................................................................................. B. vexillum Breddin

9. Coxae, trochanters, base and apex of femora, base of tibiae and tarsi yellowish.......................... ................................................................................................................ B. coxalis Breddin

Legs uniformly castaneous to dark-castaneous.................................. B. geniculatus (Fabricius)