Stethynium, Enock, 1909

Huber, John T., Read, Jennifer D. & Triapitsyn, Serguei V., 2020, Illustrated key to genera and catalogue of Mymaridae (Hymenoptera) in America north of Mexico, Zootaxa 4773 (3), pp. 1-411 : 342-343

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).

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).

Figures

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.

FIGURES 980–984. Stethynium triclavatum Enock, head except 984. 980, anterior; 981, posterior; 982a, lateral; 982b, lateral (internal) showing ocular apodeme; 983, dorsal; 984, antenna. Scale bars=100 μm.

FIGURES 985, 986. Stethynium triclavatum Enock, mesosoma. 985, dorsal; 986, lateral. Scale bars=100 μm.

FIGURES 987, 988. Stethynium triclavatum Enock, male. 987, wings; 988, habitus, same data as Fig. 979. Scale bars: 987=100 μm; 988=500 μm

FIGURES 991–994. Stethynium triclavatum Enock, male. 991, head, anterior; 992, head, posterior; 993a, metasoma, dorsal; 993b, genitalia seen through gaster; 994, antenna. Scale bars: 991–993=100 μm; 994=200 μm.