Merodon bombiformis Hull 1944

Key to the species of the Merodon bombiformis species group

Female of M. vittatus sp. nov. is unknown.

1. Species with reddish-yellow/golden face, frons (Figs 9A, 15A), lateral sides of scutum (Figs 10A, 14A) and most of terga (Figs 5A, 14A); oral margin reduced (Fig. 9A); antennal segments very short (Fig. 4A)...................................................................................... Merodon bombiformis Hull, 1944

− Species with mostly dark face, frons, lateral sides of scutum and most of terga; oral margin protruded (Fig. 9B–F); antennal segments longer (Fig. 4B–F)......................................................................... 2

2. Large, dark/brownish species (body length 10–14 mm) with distinct pollinose fasciae on terga 2–4 covered with whitish to yellow pile (Figs 5B–D, 14B–C); tergum 4 with broad medial pollinose fasciae; scutum with five longitudinal pollinose vittae; face dark, mostly covered with gray pollinosity......................................................................................................................................... 3

− Smaller, black species (body length 6–9 mm) without or with less distinct pollinose fasciae on terga 2–4 (Fig. 5E–F); tergum 4 with less distinct medial pollinose fasciae; scutum without or with indistinct pollinose vittae; face shiny black without pollinosity...................................................... 5

3. Metafemur with shorter and less dense pilosity, especially ventro-laterally (Figs 6B–C, 16B); eye contiguity longer, more than 15 ommatidia long; anterior margin of surstyle angular in lateral view (Figs 7D, 13D).................................................................................................................................. 4

− Metafemur with long and dense pilosity, especially ventro-laterally (Figs 6D, 16C); eye contiguity shorter, about 10 ommatidia long; anterior margin of surstyle rounded in lateral view (Fig. 7A: ams)........................................................................................ Merodon zebra Vujić & Radenković sp. nov.

4. Male genitalia with narrow, S-shaped posterior lobe of surstyle, gradually narrowing toward tip (Fig. 7D) (female unknown).............................................. Merodon vittatus Vujić & Likov sp. nov.

− Male genitalia with broad posterior lobe of surstyle, slightly curved, with almost parallel sides and rounded apex (Fig. 13D)........................................................ Merodon multifasciatus Curran, 1939

5. Terga 2–4 without pollinosity, only with medial fasciae of whitish pile (Figs 5E, 14D) (in female a pair of indistinct pollinose fasciae on tergum 4).......... Merodon lotus Vujić & Radenković sp. nov.

− Terga 2–4 with pairs of medial pollinose fasciae, covered with whitish to yellowish pile (Figs 5F, 14E)..................................................................................................... Merodon nasicus Bezzi, 1915