S. Mahunka szerk.: Folia Entomologica Hungarica 64. (Budapest, 2003)

Lateral frontal carinae weak (Figs 9E-F); Fl of male shorter and other (Figs 13H-I); face black in both sexes 19 19. Pedicel usually longer than broad in both sexes, Fl of male flattened on the inner surface, not strongly curved or apically expanded not more than basally (Fig. 13H) S. radiatus Mayr, 1872 11 Pedicel as long as broad or only slightly longer than broad; Fl of male concave on the inner surface, twisted and expanded apically (Fig. 131) S. pallipes Hartig, 1840 (= albipes Hartig, 1841, syn. n., = nervosus Hartig, 1840, syn. n.)

3 The Synergus genus is the most rich one in species and has the most diverse host associations. Synergus species are related to cynipid galls on Quercus spp., except two Nearctic species that are related to cynipid galls on Castanea. The majority of Synergus species are found in galls on deciduous Quercus species, two species in the Mediterranean region attack only galls on evergreen oaks and three species associate with galls on both deciduous and evergreen oak species. Them majority of species of the Section I (Mayr, 1872) are univoltine and usually attacks woody, lignified galls. When they have two annual generations, the adult's morphology does not varied significantly (Nieves-Aldrey & Pujade-Villar 1985, Pujade-Villar 1992). The majority of species from the Section II are bivoltine (occasionally with a third partial generation) and rarely attack large and woody galls and adult's morphology of different generations can vary significantly (NievesAldrey & Pujade-Villar 1985, Pujade-Villar 1992). All the species from the Section II and a few from Section I belongs to lethal inquilines. Monzen (1953) listed six species of Synergus from Eastern Palaearctic, all from Japan: S. atamiensis Ashmead, 1904, S. gifuensis Ashmead, 1904, S. hakonensis Ashmead, 1904, S. japonicus Walker, 1874, S. jezoensis Uchida et Sakagami, 1948, and S. mizunarae Shinji, 1940. The only species recorded after its description is Synergus japonicus. Masuda (1959) recognised two forms of S. japonicus: type "A" and type "B", on the basis of differences in life cycles and impact of the gall structure. Later, Abe (1990,1992) extended the biological studies on "S. japonicus" species complex. The ecological differences, which were found by previous authors, are supported by morphological characters separating two species in the "Synergus japonicus" complex: Synergus japonicus and S. gifuensis Ashmead, 3 S. radiatus and S. pallipes (= albipes, syn. n., nervosus, syn. n., see below and Appendix 3) are also closely related species, often confounded, have more than one generation per year and also geographical variations and, thus frequently cannot be reliably distinguished morphologically (see Eady & Quinlan 1963, Wiebes-Rijks 1979, Nieves-Aldrey & Pujade-Villar 1986, Williams 2002).