AbstractThe first instar larva ofPromecognathus laevissimus(Dejean) is described, representing the first species of Promecognathus known in the larval stage. The larva is autapomorphic in having: (1) additional setae, often in great number, on many sclerites of the body, (2) a transverse, not bulbous, sensory area located ventrally and laterally at the apex of antennomere III, and (3) the marginal area of the mesonotum, metanotum and abdominal tergites I‐VI more expanded than usual in carabid larvae. No evidence was found from the larval morphology ofP.laevissimusto indicate the sister group of the Promecognathin