Key to species of Macronemus

1. Elytra with large band of whitish scaly pubescence on apical 1/4; protibiae slightly curved, almost linear. Brazil (Espírito Santo, Rio de Janeiro) (Figs 1–4)...................................................... M. analis (Pascoe, 1866)

- Elytral scaly pubescence otherwise colored; protibiae curved................................................... 2

2. Profemora with inferior margin projected near base and with longitudinal, glabrous band where the protibial spine fits (Figs 11, 16–17); males with protibiae with a single spur and a long apical spine (Figs. 8, 16) and with fifth urosternite apical margin strongly bisinuate (Figs 7, 14)............................................................................ 3

- Profemora without inferior margin projected near base and without glabrous band; protibiae with two spurs, without a spine (Figs 22–23) and males with fifth urosternite apical margin from straight to slightly sinuous (Fig. 3)....................4

3(2). Integument brown; antennae, exceeding elytral apices, in both sexes, at antennomere 5; elytra with triangular postmedian band, parallel to the suture of dark-brown scaly pubescence and elytral basal third without defined band of brown scaly pubescence. Peru, French Guiana, Brazil (Amazonas, Pará, Rondônia) (Figs 5–11)................. M. rufescens (Bates, 1862)

- Integument dark-brown to black; antennae, exceeding elytral apices, in both sexes, at antennomere 6; elytra without triangular postmedian band, parallel to the suture of dark-brown scaly pubescence and elytral basal third with a curved band of brown scaly pubescence, reaching the suture. Brazil (Amapá, Amazonas), French Guiana (Bélizon) (Figs 12–17).................................................................................................... M. giuglarisi sp. nov.

4(2). Pronotum with one pair of projections flattened at apex (Fig. 24); elytral basal third with two eye-shaped spots of dark-brown scaly pubescence. Brazil (Bahia to Santa Catarina), Argentina (Figs 18–26)......................... M. mimus sp. nov.

- Pronotum with one pair of projections rounded at apex; elytral basal third otherwise colored.......................... 5

5(4). Elytral apex with one pair of subparallel bands of whitish scaly pubescence; apex of fifth urosternite in females almost not excavated (Figs 10, 15). Brazil (Minas Gerais to Rio Grande do Sul), Paraguay (Figs 27–32).. M. filicornis (Thomson, 1861)

- Elytral apex with one or more pairs of oblique bands of whitish scaly pubescence; apex of fifth urosternite in females deeply excavated (Fig. 4).....................................................................................6

6(5). Elytral dorsal and lateral surfaces thickly rugose. Mexico (Veracruz) to Panama, Colombia, Venezuela, Ecuador, Bolivia (Figs 33–38).......................................................................... M. asperulus White, 1855

- Elytral dorsal and lateral surfaces semismooth to slightly rugose. Surinam, French Guiana, Brazil (Amapá, Amazonas, Pará, Rondônia) (Figs 39–42)....................................................... M. antennator (Fabricius, 1801)