Key E: Species of the Sphex gaullei group

1. Female: scutellum and clypeus completely ferruginous (Figs 104, 106, 108). Male: at least lower/inner third of clypeus ferruginous; facial setae golden or silvery.......................................2

– Female: scutellum and at least upper half of clypeus black (Figs 100–102). Male: clypeus nearly or completely black; facial setae never golden..................................................................4

2. Petiole and metasomal segment I bright ferruginous (Fig. 108). Female: meso- and metapleurae ferruginous; basal half of forewing with conspicuous yellow tinge and cellular wing area not infuscate. Male: erect clypeal and paraocular setae silvery ...... S. schmideggeri sp. nov.

– Petiole and metasoma black (Figs 104–107). Female: meso- and metapleurae black; cellular area of forewing either hyaline and without yellow tinge or notably infuscate in apical part with at most inconspicuous yellow tinge near wing base. Male: erect clypeal and paraocular setae golden......3

3. Female: cellular area of forewing hyaline (Fig. 29), usually without violet iridescence; pronotal lobe predominantly black. Male: hindwing and cellular area of forewing hyaline (Fig. 30) ....... .................................................................................................................... S. jansei Cameron, 1910

– Female: apical half of forewing markedly infuscate (Fig. 31), with violet iridescence; pronotal lobe predominantly ferruginous. Male: cellular area of forewing infuscate in apical half, or at least apical margin of hindwing infuscate (Fig. 32) .................................... S. gaullei Berland, 1927

4. Wings hyaline. Erect facial and propodeal setae silvery (Figs 102–103). Petiole length more than 3× its medial width ....................................................................... S. pruinosus Germar, 1817

– Wings fuscous. Erect facial and propodeal setae black (Figs 100–101). Petiole length less than 2.5 × its medial width ................................................................................... S. decipiens Kohl, 1895