Key to species complexes and species of the Merodon bessarabicus subgroup

(Distribution data are included)

MALES

1 Tergites only with pale pile..............................................................................2

- Tergites with pale pile and stripes of black pile..............................................................7

2 Mesonotum only with pale pile...........................................................................3

- Mesonotum with both pale and black pile, black ones present at least near wing basis............................... 5

3 Tergite II (and III) with a pair of orange lateral spots............... Merodon luteomaculatus complex (South-East Europe)

- Tergites uniformly dark brown to black (Fig. 9 a)............................................................ 4

4 Tergites II and III with a pair of lateral microtrichose stripes (Fig. 9 a); hind femur black except for paler apical margin (Fig. 9 b); pile on eyes black in upper 1/2....................................... Merodon legionensis (Iberian Peninsula)

- Tergites usually without microtrichia (Fig. 7 a); hind femur with yellowish apical fifth, including triangular process (Fig. 7 c); pile on eyes black in upper 1/3.................................................... Merodon flavicornis (France)

5 Black pile on mesoscutum distributed only between wing bases (Fig. 15 a).............................................................................. Merodon ambiguus complex (Aegean islands, Balkan and Anatolian Peninsulas)

- Pile on at least posterior half of mesoscutum black (as in Fig. 5 a)................................................ 6

6 Eyes in upper third with black pile; hind femora in apical half with black pile; almost all surface of mesoscutum covered with black pile, except pale stripes of pile on anterior margin; anterior half of scutellum with black pile, posterior half with pale pile (Fig. 4 b)........................................................... Merodon adriaticus sp. n. (Adriatic coast)

- Eyes and hind femora mostly covered with pale pile; mesoscutum with black pile on posterior half; scutellum covered with pale pile (Fig. 12 b)......................................................... Merodon rufipes (Eastern Europe)

7 Mesoscutum covered with pale pile............... Merodon sapphous complex (Aegean islands and Anatolian Peninsula)

- Mesoscutum with at least wing bases bearing black pile..................................................... .. 8

8 Eyes in upper half covered with black pile............. Merodon bessarabicus complex (Anatolian and Balkan Peninsulas)

- Pile of eyes pale or with few black pile in apical fifth........................ Merodon quercetorum (Iberian Peninsula)