Stridulatory apparatus in the Italian species of the genus Laccobius erichson (Coleoptera : Hydrophilidae)

Abstract The stridulatory apparatus in males of the Italian species of the genus Laccobius Erichson (Coleoptera : Hydrophilidae) was examined by means of scanning electron microscope. In Laccobius , there is an elytron-uropleural type stridulatory apparatus. The “pars stridens” is situated on the 3rd abdominal pleurite and has an eulamellated structure. The “plectrum” is located on the inner elytron face. Significant subgeneric differences were found mainly in the extent of the areas, which make up the pars stridens and in the type of pleural denticulations. Differences in the plectrum cusps are also indicated.