Naupactus chordinus is characterized by the dense brownish-grey or green vestiture composed of lanceolate scales and fine suberect setae, anteriorly directed on the pronotum. The antennae are broad; the pronotum is subcylindrical; the scutellum small, almost indistinct; the elytra are oval, elongate, almost straight at base, with rounded, reduced humeri, and convex intervals; the corbels of the hind tibiae are absent.

Females are usually brownish-grey and broader than males; males are slender, usually green, with ventrite V more elongate.

Glycine max L. (Merr.) (Fabaceae) in Buenos Aires province.

It is mainly associated with native vegetation of Pampean and Espinal biogeographic provinces.