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 F 1 –F 6 pale and clava with C 2–3 pale brown ( Figs 2, 7)......................................... F. erdoesi Bouček

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

4 F 6 pale and 0.7 × as long as wide ( Fig. 8); F 1 –F 3 shorter ( Fig. 8), F 1 + 2 + 3 = 3.7 × as long as wide; fore femur pale ( Fig. 3)......................................................................................... .. F. reptans (Nees)

- F 6 dark and 1.4 × as long as wide ( Fig. 9); F 1 –F 3 longer ( Fig. 9), F 1 + 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)