Cryptolarynx falciformis is a species of beetle of the family Curculionidae. It is found in South Africa, where it is only known from the type locality of Tulbagh in the Western Cape province.
Adults reach a length of about 3.2 mm and have an integument black body, with the antennae and tarsi reddish.
This species name refers to the falcate (sickle-shaped) copulatory sclerite in the endophallus of this species.