The pectoralis species-group of Nearctic PachybrachisChevrolat, 1836 is defined and revised. The group is composed of seven species: Pachybrachis clarki Barney, Pachybrachis diversus Fall, Pachybrachis obsoletus Suffrian, Pachybrachis peccans Suffrian, Pachybrachis pectoralis (F. E. Melsheimer), Pachybrachis sobrinus Haldeman, and Pachybrachis tridens (F. E. Melsheimer). Pachybrachis sobrinus Haldeman is elevated to full species status (revised status), while Pachybrachys sticticus Blatchley and Pachybrachys oculatus Suffrian are designated as synonyms of P. sobrinus. Lectotypes are designated for Cryptocephalus pectoralis Melsheimer, P. sobrinus, Pachybrachys sticticus Blatchley, Cryptocephalus tridens Melsheimer, Cryptocephalus flavicornis Melsheimer, Pachybrachis mollis Haldeman, and Pachybrachys diversus Fall. Thirty-six new state records are confirmed. A key to species is given, and a description, figure, and range map is presented for each species.