Pronotum median longitudinal grove

Pronotum median longitudinal grove or depression absent.

Weakly developed

© Nathan Lord, 2007
Deretaphrus puncticollis pronotum dorsal

Pronotal median longitudinal groove or depression weakly developed, not interrupted to form two portions.

Well developed

© Nathan Lord, 2007
Deretaphrus piceus pronotum dorsal

Pronotal median longitudinal groove well developed, sharply impressed, usually interrupted to form a distinct anterior portion and a basal portion. Anterior portion usually foveate, always distinctly shorter than basal portion.