We studied 18 cerambycid beetle species native to South America. Seventeen represent new state records in Brazil. Particularly, Chlorethe scabrosa Zajciw, 1963 is newly reported for the state of Rio de Janeiro with exclusion of C. brachyptera Zajciw, 1963. The Brazilian state of the type locality of Dufauxia guaicurana Lane, 1955 is fixed. Pirangoclytus mendosus (Galileo & Martins, 1996) is synonymized with P. mniszechii (Chevrolat, 1862), and its holotype is a female. Variation on Trypanidius maculatus Monné & Delfino, 1980 is commented. New country and department records for Paraguay are also provided.