Key to species of Colacus Ohaus, 1910

(modified from Neita-Moreno 2015)

1. Head, pronotum, and elytra black. Pronotum with a pair of tubercles and a small, anterior fovea. Elytra rugopunctate, punctures strongly impressed.................................................................................... 2

- Head and pronotum black, elytra yellow or red. Pronotum lacking tubercles. Elytra punctate, punctures shallow.......... 3

2. Cephalic tubercle entire, sharp, conical (Fig. 7D). Femora ventrally black (Fig. 6B). External margin of mandibles slightly concave (Fig. 7B).............................................................. Colacus morio Ohaus, 1910

- Cephalic tubercle apically emarginate, compressed, transverse (Fig. 2A). Femora ventrally dark red (Fig. 1B). External margin of mandibles convex (Fig. 3E)....................... Colacus rubrofemoratus Sobral, Morais, & Grossi, new species

3. Clypeal apex sharp, bristles absent. Labium, in lateral view, slightly convex. Lateral edges of paraglossae as long as labial palpomere I (see Fig. 10a in Neita-Moreno 2015: 193)................................ Colacus bicolor Ohaus, 1910

- Clypeal apex truncate, slender bristles present. Labium, in lateral view, strongly convex. Lateral edges of paraglossae shorter than labial palpomere I (see Fig. 29a in Neita-Moreno 2015: 197)................ Colacus moroni Neita-Moreno, 2015