The presternal area is described for adult females and males of the eight Scandinavian species of the genus Haemogamasus. This area contains suture lines with more or less conspicuous denticles. The denticles cover the posterior wall of the postcapitular furrow and probably act as a barrier to overflow of liquid accumulation during feeding. The presence of denticles in the presternal area may be correlated with, and an extension of, the elaboration of rows of deutosternal denticles on the ventral face of the subcapitulum. The configuration of the denticles can be used as a diagnostic character at the species level. Keys to the species, based on this character as well as others of adult females and males, are given.