The complex Speonomus delarouzeei combines 6 species which were previously synonymized. Using behavioural data, based on 12 populations, the author assesses the validity of 4 species and points out the occurrence of 2 species as yet undescribed. Constant and important differences during the mating appear between these different species. They concern the number of behavioural steps, the duration, the number of clappings of antennae, the abdominal male movements and the rubbing of female abdomen. The results of crossing experiments between different species indicate a prezygotic reproductive isolation with atypical matings and no sperm deposit. Between the populations of S. delarouzeei s. str., having the same mating pattern some small differences observed do not represent barriers to hybridization and they may represent a speciation event at a very early stage.