Description. Head. Anterior border of labrum thin, slightly bisinuate to nearly straight, anterior angles rounded. Frontoclypeal suture between internal tubercles lacking. Frontal ridges poorly marked to almost absent, internal tubercles small to very small, distinct. Median frontal structure (MFS) with central horn, short, apically rounded and not free; lacking setae on each side of horn. Ligula between insertions of labial palpi narrow and deeply divided by longitudinal sulcus, anteriorly triangular, apex acute; surface shiny. Lateral lobes of mentum flat; center of mentum anteriorly bilobate with or without punctured setae. Last segment of labial palpus large, 1/2 or more than 1/2 length of length second segment. Dorsal mandibular tooth large, with acute angle in lateral view; aspect of mandibles in ventral view rounded; external part of mandible lacking ventral keel. Thorax. Pronotum opalescent and smooth (some specimens with bluish cast), lateral fossae lacking setae and punctation. Scutellum with small punctate setae. Mesosternum with setae on posterior sides and mesosternellum. Metasternal disk delimited partially or totally by setose punctation, marginal groove narrow. Elytra. Opaque and strongly grooved; elytral striae marked with fine punctation; interstriae covered with annular closed (to reticulated) micropunctation, only visible at great magnification. Setae present in anterior margin of all interstriae, and abundant on humeri. Interstria VIII with setae from the humerus to the first 1/6 of the elytron to slightly past the middle; interstria IX with setae at or slightly past middle; interstria X with setae from humerus to posterior apex. Legs. Mesotibiae with two (occasionally one, three or four) spines on external border.