Key to species of Nasuconia Sakakibara

1 Frontoclypeus in profile straight (Figs. 3A–C); in dorsal view, posterolateral area of pronotum tapered not projected laterally (Figs. 4A–C); posterior pronotal process lacking a transverse carina; R 4+5 only gradually curved distally... 2 ( lineosa -group)

- Frontoclypeus in profile distinctly curved downwards (Figs. 3D–G); in dorsal view, posterolateral area of pronotum rounded projected laterally (Figs. 4C–G); posterior pronotal process with a transverse carina (may be indistinct Fig. 1C tr c); R 4+5 distinctly bent distally (Fig. 6B)...................................................... 4 ( curculionoida -group)

2 In lateral view, preapical part of posterior pronotal process higher than metopidium (Fig. 3A)................. N. lineosa

- In lateral view, preapical part of posterior pronotal process about the same height as metopidium (Figs. 3D–C)........... 3

3 Frontoclypeus extended 2/3 of its length beyond suprantennal margin (Fig. 2C); in lateral view, head (vertex and frontoclypeus) in the same oblique line as metopidium (Fig. 3C)..................................................... N. nanica

- Frontoclypeus extended ½ of its length beyond suprantennal margin (Fig. 2B); in lateral view, head (vertex and frontoclypeus) obliquely directed forward (Fig. 3B)........................................................... … N. catarina

4 Posterior pronotal process with a transverse carina; pronotum with elevated longitudinal lines or nodes, not densely pubescent (Figs. 3D–F)......................................................................................... 5

- Posterior pronotal process without a distinct transverse carina; pronotum without elevated longitudinal lines or nodes, densely pubescent (Fig. 3G)..................................................................... N. yasuni sp. nov.

5 Pronotum sculpture with distinctive yellow longitudinal lines, or nodes, dark brown in color; proepisternum not enlarged …6

- Pronotum sculpture without distinctive yellow longitudinal lines, or nodes, black in color; proepisternum enlarged......................................................................................... N. ellenfutterae sp. nov

6. Pronotum with yellow longitudinal lines, not nodes (Fig. 4D); preapical part of posterior pronotal process evenly convex (Fig. 3D).................................................................................... N. curculionoida

- Pronotum with yellow discontinuous nodes (Fig. 4E); preapical part of posterior pronotal process with small cone-shaped humps (Fig. 3E)..................................................................... N. guianensis sp. nov.