Key to the species of pollen wasps from the Caucasus

1. Ventral margin of clypeus truncate (Fig. 9A); flagellum of antenna not distinctly club-shaped (Fig. 9D); notaulices distinct at whole length on mesoscutum; forewing not folded longitudinally in rest and in death; large species (total body length more than 15 mm)............................. Genus Ceramius Latreille, 1810 (one species Ceramius caucasicus André, 1884)

- Ventral margin of clypeus at least slightly emarginate (Figs 1E, 5E, 6D, 7D, 8B, C, 9B, C, F); flagellum of antenna distinctly club-shaped, with articles A8–A12 noticeably enlarged in diameter (Figs 1E, 5E, 6D, 7D, 8B, C, 9B, C, F–I), sometimes A12 slightly curved backwards forming a hook-like projection at distal end of flagellum (Fig. 9E); notaulices obsolete; forewing variable; smaller species (total body length at most 10 mm).................................................... 2

2. Propodeum with wide lateral lamella separated from lateral apex of postero-lateral process of propodeum by more or less distinct emargination (Figs 1G, 10A–C); metasoma with sharply produced lateral margins of terga forming more or less developed teeth (Figs 1B, 5B); metasomal sterna rather flat; antennal scape less than 1.5 times longer than pedicel (Figs 1E, 5E, 9F); forewing can be folded longitudinally in rest and in death (Genus Celonites Latreille, 1802).................................. 3

- Propodeum without such lateral lamella; metasoma with lateral margins of terga not produced (Fig. 7B); metasomal sterna convex; antennal scape more than 1.5 times longer than pedicel (Figs 6D, 7D, 8B, C, 9B, C); forewing variable......... 15

3. Females............................................................................................. 4

- Males (unknown in Celonites carpenteri)................................................................. 10

4. Frons and clypeus covered with especially long setae, 2–3 times as long as diameter of median ocellus (Fig. 9H); axilla of scutellum without distinct lateral projection lying on tegula (Fig. 10D); outline of emargination between lateral lamella and postero-lateral process of propodeum broad and shallow (see Fig. 10A); posterior margins of terga II–V strongly crenulate (Fig. 10H)....................................................................... Celonites laetus Panfilov, 1968

- Frons and clypeus covered with shorter setae, about as long as diameter of median ocellus (Fig. 9I) or shorter (Figs 1B, 9G, J); axilla of scutellum variable; outline of emargination between lateral lamella and postero-lateral process of propodeum variable; posterior margins of terga II–V less crenulate (Fig. 10I, K) or not crenulate (Figs 1D, 10J)........................... 5

5. Frons and clypeus densely covered with stiff setae bearing at least small, knob-like, spherical swelling at distal end, forming pollen brush, knobbed setae on frons about as long as diameter of median ocellus (Fig. 9I); axilla of scutellum without distinct lateral projection lying on tegula (see Fig. 10D); outline of emargination between lateral lamella and postero-lateral process of propodeum broad and shallow (Fig. 10A); head in frontal view not wider than long....... Celonites tauricus Kostylev, 1935

- Frons and clypeus less densely covered with setae pointed at distal end, setae on frons usually shorter than diameter of median ocellus (Figs 1B, 9G, J); axilla of scutellum with distinct lateral projection lying on tegula (Figs 1A, 5A, 10E); outline of emargination between lateral lamella and postero-lateral process of propodeum deeper and narrower (Figs 1G, 10B, C); head in frontal view at least 1.2× as wide as long................................................................. 6

6. Gena very narrow, much narrower than diameter of lateral ocellus (Fig. 9G); head 1.4–1.6× as wide as long, with at least some yellow markings (Fig. 9F) ( C. osseus -complex, see also Mauss et al. 2022a)...................................... 7

- Width of gena in front of ocular sinus at least about as diameter of lateral ocellus (Figs 1B, 9J); head 1.2–1.3× as wide as long, without yellow markings (Fig. 1E)........................................................................ 9

7. Outline of emargination between lateral lamella and postero-lateral process of propodeum with narrow short neck, its apical end small oval-shaped (fig. 7c in Mauss et al. 2022a); bulged shiny rim of sternum VI postero-laterally strongly curved in medial direction, running obtuse to nearly transverse at posterior end resulting in blunter appearance of posterior end of sternum VI (fig. 8c in Mauss et al. 2022a); posterior section of bulged rim of sternum VI partly interrupted by large depressions of macropunctures (fig. 8c in Mauss et al. 2022a); dorso-posterior margin of sternum VI with distinct irregularly serrated crystalline horizontal lamella situated immediately above posteriorly directed stiff setae, dorso-medially fused with median spine and somewhat more protruded at postero-lateral edges (fig. 8h, i in Mauss et al. 2022a)............................................................................................. Celonites cagrii Mauss & Yildirim, 2022

- Outline of emargination between lateral lamella and postero-lateral process of propodeum with broad short neck, its apical end medially enlarged (Fig. 10B and fig. 7f, g in Mauss et al. 2022a); bulged shiny rim of sternum VI forms regular curve postero-laterally resulting in more pointed appearance of posterior end of sternum VI (fig. 8b in Mauss et al. 2022a); posterior section of bulged rim of sternum VI not or barely interrupted by large depressions of macropunctures (fig. 8b in Mauss et al. 2022a); dorso-posterior margin of sternum VI at most with simple weak translucent cuticula crest (fig. 8g in Mauss et al. 2022a)... 8

8. Head in frontal view more triangular, outline of compound eye less strongly curved, 1.45–1.53× as wide as long (fig. 4e in Mauss et al. 2022a); light coloration less extended, mesoscutum usually black (fig. 6c in Mauss et al. 2022a) and outside of mid and hind tibia with dark ring-like markings; dark color of head and mesosoma deep black........................................................................................... Celonites ivanovi Mauss & Fateryga, 2022

- Head in frontal view more elliptic, outline of compound eye nearly semi-circular, 1.50–1.62× as wide as long (Fig. 9F and fig. 4d in Mauss et al. 2022a); light coloration more extended, with yellow spot on mesoscutum (fig. 6d in Mauss et al. 2022a) and outside of mid and hind tibia completely yellow; dark color of head and mesosoma black, partly with more or less brownish to reddish shade.............................................................. Celonites osseus Morawitz, 1888

9. Punctation on terga coarse (Fig. 1D); posterior margins of terga II–V deflected upwards (Fig. 1B); fully extended proboscis much shorter than body (Fig. 1B); mesepisterna black.................. Celonites carpenteri Fateryga & Mauss, sp. nov.

- Punctation on terga much finer (Fig. 10J); posterior margins of terga II–V flat; fully extended proboscis much longer than body (see Fig. 5B); dorsal mesepisternum with large pale yellow spot partially replaced posteriorly by ferruginous (see Fig. 5B)........................................................................ Celonites tudesculptus Kostylev, 1935

10. Antenna ventrally with two oval-shaped tyloids; tergum VII quadrilobed, since median lobe medially distinctly emarginate (Fig. 10F); frons and clypeus densely covered with stiff setae bearing at least small, knob-like, spherical swelling at distal end, forming pollen brush, knobbed setae on frons about as long as diameter of median ocellus (see Fig. 9I); axilla of scutellum without distinct lateral projection lying on tegula (Fig. 10D)......................... Celonites tauricus Kostylev, 1935

- Antenna ventrally with three oval-shaped tyloids; tergum VII variable; setation of frons and clypeus variable but not consisting of knobbed setae; axilla of scutellum variable.............................................................. 11

11. Tergum VII quadrilobed, since median lobe medially distinctly emarginate (see Fig. 10F); frons and clypeus covered with especially long setae, 2–3 times as long as diameter of median ocellus (see Fig. 9H); axilla of scutellum without distinct lateral projection lying on tegula (Fig. 10D); posterior margins of terga II–VI strongly crenulate (see Fig. 10H)............................................................................................ Celonites laetus Panfilov, 1968

- Tergum VII trilobed (Figs 5C, 10G, K); frons and clypeus covered with very short setae, much shorter than diameter of median ocellus (see Fig. 5B, 9G, J); axilla of scutellum with distinct lateral projection lying on tegula (Figs 1A, 5A, 10E); posterior margins of terga II–VI at most weakly crenulate (Fig. 10K) or not crenulate (Fig. 5C).............................. 12

12. Median lobe of tergum VII very broadly rounded (Fig. 5C); width of gena in front of ocular sinus about as diameter of lateral ocellus (Fig. 5B); frons without yellow markings (Fig. 5E); sternum VIII posteriorly broadly emarginate, with short process at center (Fig. 5D); harpide posteriorly bifurcate (Fig. 5D)......................... Celonites tudesculptus Kostylev, 1935

- Median lobe of tergum VII moderately broad to comparatively narrow (Fig. 10G, K); gena very narrow, much narrower than diameter of lateral ocellus (see Fig. 9G); frons with at least some yellow markings; sternum VIII acutely produced, running into two tapering lobes at posterior end with deep median incision between them (fig. 14d–f in Mauss et al. 2022a); harpide spatula-like (figs 12d, e, f, 13d, e, f in Mauss et al. 2022a) ( C. osseus -complex, see also Mauss et al. 2022a)............ 13

13. Genitalia broader at base (figs 10d, 11d in Mauss et al. 2022a), cupula wider, less curved (in ventral view; figs 12d, 13d in Mauss et al. 2022a); lateral margin of harpide without concavity near apical end due to broad lamella along postero-lateral margin of harpide (figs 12d, 13d in Mauss et al. 2022a); median lobe of tergum VII broader at base between postero-lateral angles (Fig. 10G and fig. 9c in Mauss et al. 2022a)................................. Celonites osseus Morawitz, 1888

- Genitalia narrower at base (figs 10e, f, 11e, f in Mauss et al. 2022a), cupula narrower, more strongly curved (in ventral view; figs 12e, f, 13e, f in Mauss et al. 2022a); lateral margin of harpide with shallow concavity near apical end (figs 12e, f, 13e, f in Mauss et al. 2022a); median lobe of tergum VII narrower at base between postero-lateral angles (Fig. 10K and fig. 9d, e in Mauss et al. 2022a)................................................................................... 14

14. Head in frontal view more triangular (fig. 9a in Mauss et al. 2022a); median lobe of tergum VII markedly produced, its posterior margin and adjacent posterior translucent lamella entirely convex (Fig. 10K and fig. 9d in Mauss et al. 2022a); sternum VIII with longitudinal depression at center largely oval, lancet-like tips and postero-median incision between them broader (fig. 14e in Mauss et al. 2022a); aedoeagus with narrowly rounded distal end, its lateral sides noticeably converging (figs 10e, 11e in Mauss et al. 2022a); outline of emargination between lateral lamella and postero-lateral process of propodeum with broad short neck, its apical end medially enlarged (fig. 7g in Mauss et al. 2022a)........... Celonites ivanovi Mauss & Fateryga, 2022

- Head in frontal view strongly oval (fig. 9b in Mauss et al. 2022a); median lobe of tergum VII moderately produced, its posterior margin weakly concave in middle, with adjacent posterior translucent lamella fairly emarginate (fig. 9e in Mauss et al. 2022a); sternum VIII with longitudinal depression at center more elongate, lancet-like tips and postero-median incision between them narrower (fig. 14f in Mauss et al. 2022a); aedoeagus with broadly rounded distal end, its lateral sides only weakly converging (figs 10f, 11f in Mauss et al. 2022a); outline of emargination between lateral lamella and postero-lateral process of propodeum with narrow neck, its apical end small oval-shaped (fig. 7c in Mauss et al. 2022a)...................................................................................................... Celonites cagrii Mauss & Yildirim, 2022

15. Very small species (total body length about 3–4 mm); forewing can be folded longitudinally in rest and in death; larger spur of hind tibia simple; male antenna short, reaching at most coxae of forelegs (Figs 7D, 8C) (Genus Quartinia André, 1884)..... .................................................................................................. 16

- Larger species (total body length about 8–10 mm); forewing not folded longitudinally in rest and in death; larger spur of hind tibia bifurcate; male antenna elongate, reaching approximately coxae of mid legs (Fig. 9E) (Genus Jugurtia de Saussure, 1854).............................................................................................. 17

16. Smaller species (total body length about 3 mm); frons and mesoscutum dull, with sparse punctures, interstices with strong reticulate microsculpture (Fig. 8A–C); tegula comparatively short, with less produced posterior end (Fig. 8A); ventral margin of female clypeus deeply emarginate (Fig. 8B); male clypeus shorter (Fig. 8C); male foretibia with less developed bulge (Figs 8D, E); basal sclerite narrow, paramere (fused stipes + harpide) slender (Fig. 8F)... Quartinia araxana Giordani Soika, 1960

- Larger species (total body length about 4 mm); frons and mesoscutum shining, with denser punctures, interstices with fine or indistinct microsculpture (Figs 6A, D, 7A, D); tegula longer, with strongly produced posterior end (Figs 6A, 7A); ventral margin of female clypeus less deeply emarginate (Fig. 6D); male clypeus longer (Fig. 7D); male foretibia with more developed bulge (Fig. 7F, G); basal sclerite broader, paramere (fused stipes + harpide) less slender (Fig. 7E)............................................................... Quartinia aliyevi Fateryga, Mauss, Proshchalykin & Maharramov, sp. nov.

17. Metasomal terga coarsely punctate (Fig. 10L); female clypeus with two dorso-lateral black spots usually fused at center (Fig. 9B); male antenna with last article A12 slightly curved backwards forming a hook-like projection at distal end (Fig. 9E)............................................................................. Jugurtia eurycara Kostylev, 1935

- Metasomal terga finely punctate (Fig. 10M); female clypeus dorsally yellow, with one central black spot (Fig. 9C); male unknown.................................................................... Jugurtia irana Kostylev, 1935