Four Scandinavian species of Platypalpus Macq. are described as new to science, viz., P. hackmani sp.n. (=P. brevicornis (Zett.) sensu Frey, 1913, 1943), P. longicornioides sp.n., P. scandinavicus sp.n. and P. tuomikoskii sp.n. The male of P. zetterstedti Chv. is described for the first time and P. subbrevis (Frey) is redescribed. Some new synonymies are established: P. interjectus (Lundbeck, 1910) is a synonym of P. difficilis (Frey, 1907), P. acroleucus Frey, 1943 of P. leucothrix (Strobl, 1910), P. calcaratus (Collin, 1926) of P. pseudociliaris (Strobl, 1910), P. agillelus (Collin, 1926) of P. pallidicoxa (Frey, 1913), and P. tantulus (Collin, 1926) is a synonym of P. cryptospina (Frey, 1909). P. varius Walk. sensu Lundbeck, 1910 is P. analis (Meig., 1830), P. nigrosetosus (Str.) sensu Frey, 1943 is P. agilis (Meig., 1822), and P. microcerus Frey, 1943 is a species of the genus Tachydromia. Four Scandinavian species of Platypalpus Macq. are described as new to science, viz., P. hackmani sp.n. (=P. brevicornis (Zett.) sensu Frey, 1913, 1943), P. longicornioides sp.n., P. scandinavicus sp.n. and P. tuomikoskii sp.n. The male of P. zetterstedti Chv. is described for the first time and P. subbrevis (Frey) is redescribed. Some new synonymies are established: P. interjectus (Lundbeck, 1910) is a synonym of P. difficilis (Frey, 1907), P. acroleucus Frey, 1943 of P. leucothrix (Strobl, 1910), P. calcaratus (Collin, 1926) of P. pseudociliaris (Strobl, 1910), P. agillelus (Collin, 1926) of P. pallidicoxa (Frey, 1913), and P. tantulus (Collin, 1926) is a synonym of P. cryptospina (Frey, 1909). P. varius Walk. sensu Lundbeck, 1910 is P. analis (Meig., 1830), P. nigrosetosus (Str.) sensu Frey, 1943 is P. agilis (Meig., 1822), and P. microcerus Frey, 1943 is a species of the genus Tachydromia.