Key of identification of the species of Scapomegas Lacordaire, 1854

1. Anterior margin of the pronotum straight behind the head (Figs. 1 E; 5C); elytra with outer subhumeral stria complete (Fig. 2 C); propygidium with strong punctuation on the whole surface (Fig. 10 B); associated with the Atlantic Forest biome........................................................................................ S. aurifer Marseul, 1887

- Anterior margin of the pronotum sinuous behind the head (Figs. 1 A, C; 5 A, B); elytra with outer subhumeral stria short (Fig. 2 A, B); propygidium without strong punctuation on the whole surface (Figs. 10 A; 3D)........................ 2

2. Lateral pronotal stria complete (Fig. 5 A); 3rd visible abdominal sternite with a sulciform row of punctures (Fig. 1 B); 8th sternite of the male terminalia, in ventral view on lateral-posterior region, at least with two longest bristles and others small (Fig. 6 A); associated with the Amazon biome..................................................... S. auritus Marseul, 1855

- Lateral pronotal stria widely interrupted at the posterior half (Fig. 5 B); 3rd visible abdominal sternite with strong punctuation but without a sulcus (Fig. 1 D); 8th sternite of the male terminalia, in ventral view on lateral-posterior region, with only one bristle (Fig. 6 B), rarely with two bristle; associated with the Atlantic Forest biome.................. S. gibbus Marseul, 1855