none. On the biology and parasitism of the gall-making sawflies, Pontania dolichura (Thoms. 1871), P. vesicator (Bremi 1849), and P. viminalis (L. 1758) (Hymenoptera: Tenthredinidae). Pontania dolichura (Thoms.), P. vesicator (Bremi), and P. viminalis (L.) are sawflies making galls on the leaves of Salix purpurea L. Oviposition and induction of gall formation occur only on young leaves. The ovipositor is driven into the plant tissue on the lower surface, a little to one or the other side of the mid-vein. The galls of P. dolichura are elongated, sausage-shaped, only produced on the upper surface of the leaf-blade, and often arranged in pairs on each side of the mid-vein. P. vesicator makes large bean-shaped galls, transected by the leaf-blade. On the contrary, the galls of P. viminalis always attach to the mid-vein on the underside of the leaf with only a small flat scar on the upper-side. They are pea-shaped with conspicuous brownish warts. Host plant specificity in Pontania generally raises many questions. Therefore complementary oviposition-tests are necessary for obtaining reliable information about host plant ranges. Especially in P. vesicator and P. viminalis embryonic development can be partially delayed. Therefore the adults of these species emerge not synchronously and the two generations of the year overlap. P. dolichura always has a prolonged diapause and thus only one generation per year is realized. Its emergence period is limited to the spring. P. vesicator and P. viminalis are attacked by different complexes of natural enemies. Among the parasitic inquilines the weevil Curculio crux F. (Curculionidae) and the chalcid Eurytoma aciculata Ratz. (Eurytomidae) are the dominant species. Two other species are of lesser importance as mortality factors of these sawflies: the curculionids Curculio salicivorus Payk. and Apion minimum HBST. (the latter in galls of P. viminalis only). Sometimes the larvae of a small, slender moth (Gypsonoma dealbana Frol., Torticidae) develop in the galls, especially of P. viminalis, and their presence is often fatal to the host. From the galls of P. dolichura no parasitic inquilines were reared. Three species of hymenopterous parasitoids develop in the galls of P. vesicator and P. viminalis: Scambus vesicarius (Ratz.) (Ichneumonidae), Pteromalus dolichurus (Thoms) (Pteromalidae), and Eulonchetron scalprum (Askew) (Pteromalidae). But only in P. viminalis are parasitoids of greater importance as mortality factors because here especially the pteromalid E. scalprum is often abundant. P. dolichura is parasitized by S. vesicarius only to a very low degree.