Key to species of the Brachiacantha dentipes group:

1 Males with cusps on the fourth ventrite (Fig. 1a)............................................... B. barberi Gordon

- Males without cusps on the fourth ventrite................................................................. 2

2 Elytra black with the posterior border red, orange or yellow (Fig. 2b)............................ B. erythrura Mulsant

- Elytron black with the posterior margin black, one or more light spots present (Figs. 1b, 6b, 8b, 9b, 11b, 13b)............ 3

3 Males with small ventral cusps, almost not visible (Fig. 5a). Basal lobe of male genitalia without apical hook (Fig. 5b).............................................................. B. brevicuspidata Nestor-Arriola & Toledo-Hernández

- Males with ventral cusps not small, always visible. Male genitalia with or without apical hook........................ 4

4 Males with head black with front red or orange. Ventral cusps not truncate (Fig. 6a).................. B. stephani Gordon

- Males with head totally yellow or orange. Ventral cusps truncate or not........................................... 5

5 Males with large ventral cusps, tuncated at apex (Fig. 7)........................................... B. tau LeConte

- Males with ventral cusps not truncated.................................................................... 6

6 Males with ventral cusps short and rounded (Fig. 8a)............................................ B. soltaui Gordon

- Males with ventral cusps not rounded..................................................................... 7

7 Males with ventral cusps widely separated, short, divergent at apex (Fig. 9a)................ B. bistripustulata (Fabricius)

- Males with ventral cusps conspicuous, not short............................................................. 8

8 Males with ventral cusps longer than wide (Figs. 10a, 11a).................................................... 9

- Males with ventral cusps wider than long (Fig. 12).......................................................... 10

9 Male genitalia with a large, rounded apical hook at the basal lobe (Fig. 10b)................................................................................................. B. robustihamata Nestor-Arriola &Toledo-Hernández

- Male genitalia with apical hook at the basal lobe not rounded (Fig. 11c)..................... B. blaisdelli Nunenmacher

10 Male genitalia with apical hook......................................................................... 11

- Male genitalia without apical hook...................................................................... 12

11 Males with ventral cusps large and subtriangular, pointed at apex (Fig. 12)....................... B. quadrillum LeConte

- Males with ventral cusps subtriangular, blunt at apex (Fig. 13a)............................... B. dentipes (Fabricius)

12 Males with ventral cusps joined by an arcuate emargination (Fig. 14)........................... B. subfasciata Mulsant

- Males with large, subtriangular cusps with blunt apex (Figs. 15a, 16a).......................................... 13

13 Male genitalia with basal lobe slender (Fig. 15b)...................... B. angulata Nestor-Arriola & Toledo-Hernández

- Male genitalia with basal lobe wide (Fig. 16b)........................ B. truncata Nestor-Arriola & Toledo-Hernández.