Cryptolarynx robustus is a species of beetle of the family Curculionidae. It is found in South Africa, where it is only known from the type locality in the Western Cape province.
Adults reach a length of about 4.5âÂÂ5 mm and have an integument black body, with the antennae, tarsi and sometimes tibiae reddish.
Specimens were collected in September, at the bases of plants of Oxalis cf. purpureain patches of Renosterveld.
The species name is derived from the Latin adjective robustus and refers to the stocky appearance of the species.