Key to species of the genus Hadrophorus:

1. Terminal antennomeres very long, more than 8 times as long as wide at apex, lacking any indication of segmentation, pronotum hemispherical with rounded sides, lacking anterior angles, base of elytra with 3 well-defined foveae..................................................................................................... H. martinkae sp. n.

- Terminal antennomeres short, less than 4 times as long as wide at apex, indication of three segments well-defined, pronotum

subrectangular with well-defined anterior angles, sides of pronotum straight, base of elytra with 3 small prolonged depressions at place of foveae...................................................................................... 2 2. Rostrum triangular, vertex with narrow, median sulcus, pronotum smooth, terminal antennomeres shorter, about 0.48 mm long, midfemora in males with large tooth.............................................. H. humerosus Fairmaire, 1898

- Rostrum rounded, vertex with median fovea, pronotum with short, dense pubescence, terminal antennomeres longer, about 0.55 mm long, midfemora in males lacking tooth...................................... H. spinipennis (Célis, 1969)