Illustrated key to genera and catalogue of Mymaridae (Hymenoptera) in America north of Mexico Author Huber, John T. Author Read, Jennifer D. Author Triapitsyn, Serguei V. text Zootaxa 2020 2020-05-12 4773 3 1 411 journal article 22231 10.11646/zootaxa.4773.1.1 d1ca4b58-0fd8-4bcb-8f81-12fc2c106b55 1175-5326 3821373 B1D8D67C-4FDC-477E-872F-E8BCD4D027FB STETHYNIUM Enock, 1909 ( Figs 979 –1010) Stethynium Enock, 1909: 452 . Type species: Stethynium triclavatum Enock, 1909 , by monotypy. Diagnosis . Body length 525–715 μm. Clava 3-segmented, the sutures between segments strongly oblique ( Fig. 984 ); mandible with 4 teeth (Fig. 1000); frenum longitudinally divided, with paramedial plate longer than wide; second phragma with rounded (convex) apex ( Figs 985 , 1001); fore wing with distinct rounded lobe behind venation ( Fig. 987 ). Male with complex asymmetrical genitalia ( Figs 993 , 1010). FIGURE 979 . Stethynium triclavatum Enock , habitus. Canada, British Columbia, Deas Island (between Vancouver and Whiterock), 9.vii.1988, A.T. Finnamore. Scale bar=500 μm. Discussion . Among the four other genera in the Nearctic with frenum longitudinally divided: Anagrus , Krokella , Platystethynium ( Platypatasson ) and Schizophragma , only Krokella also has a 3-segmented clava. Stethynium differs from it by the mandible normal, with 4 equal teeth in both sexes, fore wing more evenly rounded and with a distinct lobe behind apex of venation, and venation shorter. Nearctic hosts . Unknown. Extralimital hosts are Hemiptera : Cicadellidae , including an important pest in vineyards, Empoasca vitis (Goethe) ( Viggiani 2002 ) . Important reference . Huber (1987) .