AbstractExamination of the chromosomes shows thatHelophorus grandisIll. is a species quite separate fromH.maritimusRey. Further investigation shows that while the karyotype ofH.grandisis the same in populations from southern England, northern and central France, and the northern half of Spain, that ofH.maritimusfrom the Camargue is sufficiently different from supposedmaritimusfrom central Spain for the Spanish specimens to be regarded as a separate species, here described asH.occidentalissp.n. Aedeagophores of the three species are figured, along with additionalmaritimus‐like material.No aedeagal or other morphological features for distinguishingmaritimusandOccidentalishave been discovered. The implications of the discovery of two species of anH.maritimuscomplex are discusse