Foersterella

Hansson, Christer, 2016, The European species of Foersterella Dalla Torre (Hymenoptera: Tetracampidae), including the description of two new species, Zootaxa 4137 (4), pp. 561-568 : 562

Key to European species of Foersterella

1 Scape strongly enlarged, 2.0× as long as wide and pale ( Figs 7–10 ) (males)........................................ 2

- Scape narrow, about 3.5× as long as wide and dark ( Figs 11 , 14 ) (females)........................................ 5

2 Antennal flagellum completely dark ( Figs 4 , 10 )........................................... .. F. fuscicornis sp. nov.

- Antennal flagellum with at least two flagellomeres pale ( Figs 7–9 )............................................... 3

3 F1–F6 pale and clava with C2–3 pale brown ( Figs 2 , 7 )......................................... F. erdoesi Bouček

- F1–F3 and clava completely dark ( Figs 1, 3 , 8, 9 )............................................................ 4

4 F6 pale and 0.7× as long as wide ( Fig. 8 ); F1–F3 shorter ( Fig. 8 ), F1+2+3 = 3.7× as long as wide; fore femur pale ( Fig. 3 )......................................................................................... .. F. reptans (Nees)

- F6 dark and 1.4× as long as wide ( Fig. 9 ); F1–F3 longer ( Fig. 9 ), F1+2+3 = 5.8× as long as wide; fore femur predominantly dark ( Fig. 1 )...................................................................... .. F. angusticornis sp. nov.

5 Gaster long with apex pointed ( Fig. 13 ), 2.0–2.4× (mean 2.18, n = 7) as long as wide.................. F. erdoesi Bouček

- Gaster shorter and with apex less pointed ( Fig. 12 ), 1.2–1.7× (mean 1.47, n = 10) as long as wide.................................................................................. Foersterella spp. (not possible to identify to species)

Figures

FIGURE 14. Foersterella sp., female, habitus in lateral view, specimen length 1.2 mm. Specimen from England, Middlesex, collected and mounted by M. W. R. de V. Graham (specimen in BMNH).

FIGURES 7 – 13. Foersterella spp. 7 – 10, antenna, lateral view, male: 7, F. erdoesi Bouček; 8, F. reptans (Nees); 9, F. angusticornis sp. nov.; 10, F. fuscicornis sp. nov. 11, Foersterella sp., female, head and antennae, lateral view. 12 & 13, gaster, dorsal view, female: 12, Foersterella sp.; 13, F. erdoesi.

FIGURES 1 – 6. 1 – 4, Foersterella spp., habitus in lateral view: 1, F. angusticornis sp. nov., male holotype, specimen length 1.1 mm; 2, F. erdoesi Bouček, male non-type from Sweden (Skåne), specimen length 1.3 mm; 3, F. reptans (Nees), male non-type from Sweden (Skåne), specimen length 1.1 mm; 4, F. fuscicornis sp. nov., male holotype, specimen length 1.2 mm. 5 & 6. Head, frontal view, males: 5, F. angusticornis, holotype; 6. F. erdoesi, non-type from Sweden (Skåne).