Description.

Head: anterior border of labrum concave, anterior angles rounded. Frontoclypeal suture lacking between internal tubercles. Frontal ridges absent, internal tubercles absent or very small. Median frontal structure (MFS) with a notable central horn, relatively short and with apex free and rounded; with 0-4 setae on each side or 0-2 small punctations. Ligula between insertions of labial palpi, wide, concave or flat, without setae at center, anteriorly triangular (almost pentagonal with the base); ligula matte. Lateral lobes of mentum flat; center of mentum anteriorly bilobate. Last segment of labial palpi large, 1/2 or more than 1/2 of second segment. Dorsal tooth of mandible small, with obtuse angle in lateral view; aspect of mandibles in ventral view rounded; external part of mandible without a ventral keel.

Thorax: Pronotum shiny and smooth, lateral fossae without setae and punctation. Scutellum with small punctate setae. Mesosternum with many long setae on posterior sides and similar abundant setae on mesosternellum. Metasternal disk delimited partially or totally by setose punctation, marginal groove very narrow.

Elytra: Shiny and smooth (in some cases slightly grooved); elytral striae marked with strong punctation. Setae present in all interestriae of anterior margin and all of posterior except I, II and III; interestriae VIII, IX and X totally covered with setae; IX more densely setose in apical 1/3. In old specimens these setae appear only as punctures.

Legs: Mesotibiae with two or three spines on external border (one in some old specimens).