Key to the species of Erythropterus Melzer, 1934

1. Pronotum black........................................................ 2

Pronotum crimson, sometimes suffused dusky.. 3

2. Prothorax widest near middle, sides regularly rounded. Apical 1/4 of elytra black. Brazil (Rondônia).......... E. cuissi Napp & Monné, 2005

Prothorax widest within basal third, sides only rounded behind middle. Apical 1/10 of elytra black. S and SE Brazil, Paraguay, Argentina ....... ........................................... E. amablis Melzer, 1934

3. Elytra only slightly flattened, entirely covering abdomen and metepisterna. Apical third of elytra black. Bolivia (Figs. 3, 4)...... E. boliviensis sp. nov.

Elytra distinctly flattened, not entirely covering abdomen nor metepisterna. Only apices of elytra black or dusky ................................................. 4

4. Centre of prosternum black. Bolivia (Figs. 5, 6) ........................................................ E. kochi sp. nov.

Prosternum crimson. Venezuela .............................. ........................ E. urucuri Martins & Galileo, 2004