Coenosia, Meigen, 1826

Sorokina, Vera S., 2023, A key to the Russian species of the genus Coenosia Meigen (Diptera, Muscidae), with the description of one new species and new synonymies, Zootaxa 5389 (1), pp. 79-107 : 91-104

Key to Russian species of Coenosia

An identification key is provided to all the 77 species of the genus Coenosia that are known from Russia. It is based in part on published keys: Hennig (1961a, 1961b, 1962), Huckett (1965), Shinonaga (2003), Xue & Zhu (2006), Sorokina (2009) and Gregor et al. (2016). Macrorchis meditata (Fallén, 1825) is also included in the key because is very close to some Coenosia species ( Sorokina 2009), although still considered to be a different genus.

Some species have not been studied and have therefore been included in the key on the basis of their descriptions and/or the diagnostic characteristics proposed in the keys listed above. They are: Coenosia acuminata Strobl, 1898 , Coenosia campestris (Robineau-Desvoidy, 1830) , Coenosia flavissima Hennig, 1961 , Coenosia ghilarovi Lobanov, 1988 , Coenosia incisurata van der Wulp, 1869 , Coenosia mandschurica Hennig, 1961 , Coenosia polina Vikhrev, 2009 , and Coenosia rhaensis Hennig, 1961 .

The distribution of each species (distribution in Russia and general distribution) is given directly in the male key.

Key to males

1. Costa extending only to, or very slightly beyond, apex of R 4+5 .................................................. 2

- Costa extending to apex of M 1 ........................................................................... 3

2. Lower calypter not longer than upper one. Postpedicel with a spine-like dorsal tip.—In Asia only Siberia and China; Eurasian................................................................................... connectens (Hennig)

- Lower calypter much longer than upper one. Postpedicel without a spine-like dorsal tip, with a more or less rounded tip.— European Russia, Siberia, Far East; Palaearctic.............................................. agromyzina (Fallén)

3. Hind tibia with a median anterior seta and an anterodorsal seta at almost the same level and close together ( Fig. 9A )....... 4

- Hind tibia without an anterior seta at middle close to the anterodorsal seta, but an anteroventral seta present............. 9

4. Scutum, scutellum and abdomen shining black.—European Russia; Palaearctic.......................... atra (Meigen)

- Scutum, scutellum and abdomen not shining black........................................................... 5

5. Parafacial at least as broad as postpedicel; longest aristal hairs at least as long as width of postpedicel; outer vertical setae longer and stronger than postocular setulae.—European Russia, Siberia; Holarctic......................... tigrina (Fabricius)

- Parafacial narrower than width of postpedicel; longest aristal hairs much shorter than width of postpedicel; outer vertical setae at most as long as postocular setulae...................................................................... 6

6. All femora predominantly black.—European Russia; Holarctic, Oriental.............................. humilis Meigen

- Femora yellow, at most fore femur dorsally and mid femur apically brownish...................................... 7

7. Antenna entirely dark or flagellomere partly yellow; frontal vitta less dusted, more contrasting with fronto-orbital plates; abdomen with a midline and paired brown spots.—European Russia, Siberia, Far East; Palaearctic, Afrotropical, Oriental........................................................................................... strigipes Stein

- Antenna entirely yellow; frontal vitta densely silvery white to yellow dusted, hardly differentiated from fronto-orbital plates; abdomen grey dusted, at most with indistinct pattern.—European Russia; Holarctic, Neotropical, Afrotropical, Oriental, Australasian............................................................................. attenuata Stein

9. Last tarsomere at least of fore legs enlarged and black, contrasting with rest of tarsi which are yellow ( Fig. 9C ).......... 10

- Last tarsomere not dilated on any pair of legs.............................................................. 11

10. Last tarsomere on all legs dilated and black, contrasting with rest of yellow tarsi; one proepisternal seta; abdomen ovate.—Only European Russia......................................................................... rhaensis Hennig

- Only last tarsomere of fore legs enlarged and black, contrasting with rest of yellow tarsi; two proepisternal seta; abdomen unusually long and narrow with nearly parallel sides ( Fig. 8A ). Terminalia in Figs 3 A–C .— Georgia, Russian Caucasus............................................................................................ ozerovi Vikhrev

11. Hind tibia with strong and long preapical dorsal and posterodorsal setae close to each other ( Fig. 9B ).................. 12

- Hind tibia without strong and long close approximated preapical dorsal and posterodorsal setae...................... 13

12. Mid and hind femora and all tibia predominantly yellow.—European Russia, Siberia, Far East; Eurasian..................................................................................................... intermedia (Fallén)

- Mid and hind femora and all tibia predominantly black but fore and mid trochanters yellow.—European Russia; European........................................................................................... means Meigen

13. Lower calypter much shorter or scarcely longer than upper one................................................ 14

- Lower calypter much longer than upper one............................................................... 38

14. Oral vibrissae yellow or golden; head almost square in lateral view; frons reddish above antenna, postpedicel black, very long, 4 times as long as wide ( Fig. 10E ).— Norway, NE Russia, Far East; Holarctic........................ flaviseta (Huckett)

- With a different combination of characters................................................................ 15

15. Basal scutellar setae reduced, apical setae weak and short.................................................... 16

- Both pairs of scutellars strong and long................................................................... 17

16. Body predominantly bluish-gray ( Fig. 7A ); mid femur with anteroventral setae.—East Siberia and Far East; Holarctic.............................................................................................. ciliata Hennig

- Body predominantly yellow; mid femur without anteroventral setae.—Only European Russia........... flavissima Hennig

17. All femora black, at most with apices narrowly yellow....................................................... 18

- At least mid and hind femora yellow on basal 1/3........................................................... 23

18. Antenna including both basal segments yellow; hind tibia without a submedian posterodorsal seta.—European Russia, East Siberia; Eurasian..................................................................... dealbata (Zetterstedt)

- Antenna entirely black; hind tibia with or without a distinct submedian posterodorsal seta........................... 19

19. Ventral surface of mid and hind femora and tibia with numerous long semi-erect hairs; posterior seta on fore tibia and anterodorsal setae on mid and hind tibiae very long, at least as long as half of length of tibia ( Fig. 7C ). Terminalia in Figs 6 A–E .—European Russia,?Far East; Oriental and Palaearctic ( Japan).............................. penicillata Hennig

- Ventral surface of mid and hind legs without numerous long semi-erect hairs; setae on tibiae not longer than one-third third of tibial length......................................................................................... 20

20. Smaller species (3.5–4.7 mm); all tibiae predominantly black, only narrowly yellow basally; hind femur with 2–3 posteroventral setae on basal half; hind tibia without or with a very short posterodorsal, about 1/3 the length of the anterodorsal seta..... 21

- Larger species (5.0– 6.5mm); all tibiae brownish-yellow or yellow; hind femur with a full row of strong and long posteroventrals; posterodorsal seta of hind tibia long and only a little shorter than anterodorsal.................................... 22

21. Mid femur with a preapical anterior seta; mid tibia with a long strong anterodorsal seta, at least as long as posterodorsal seta; abdomen cylindrical, with weak brownish rounded spots; scutum with two distinct brown vittae ( Fig. 7D ). Terminalia in Figs 3 D, E .—Only Siberia and China; Asian................................................. subgracilis Xue & Cui

- Mid femur without a preapical anterior seta; mid tibia with a weak anterodorsal seta which is much shorter than posterodorsal seta; abdomen oval, with pairs of indistinct brown rectangular spots and brownish dust between them; scutum with 3 distinct brown longitudinal vittae and brownish dust between dorsocentral setae (Figures in Sorokina 2022).—Only North of Russian Far East................................................................................. galina Sorokina

22. Cerci narrow and long ( Figs 6 F, G ). All tibiae yellow ( Fig. 7F ); abdomen with rounded spots.—Only European Russia, Siberia and Russian Far East....................................................................... oralis Schnabl

- Cerci short and wide ( Figs 5 E, F ). All tibiae brownish-yellow, darkened in apical 2/3–4/5, sometimes completely yellow ( Fig. 7H ); abdomen with more or less triangular spots.—Only West Siberia and Russian Far East..... ukokensis Sorokina (part)

23. Lower calypter extremely small, shorter than the upper one, strip-like........................................... 24

- Lower calypter not strip-like, slightly protruding beyond margin of upper one.................................... 25

24. Smaller size: 3.5 mm ( Fig. 10D ). Mid femur without a strong anterior preapical seta; palpus yellow; mid and hind femora fuscous on distal half. Terminalia in Figs 6 H, I .—West Siberia, Far East; Holarctic.................... tendipes Huckett

- Larger size: 5–6 mm ( Fig. 10A ). Mid femur with a strong anterior preapical seta; palpus completely dark or yellow with dark tip; mid and hind femora yellow, with a very small dark spot at apex.—Siberia, Far East; Holarctic.................................................................................................... baicalensis Hennig (part)

25. At least apical half or third of hind femur black or fuscous on dorsal part of apex.................................. 26

- All femora completely yellow.......................................................................... 29

26. Scutum with 3 distinct brown narrow longitudinal vittae along dorsocentral and acrostichal setae, with brown dust between dorsocentral setae, reaching the apex of scutellum; mid tibia with very short anterodorsal seta which shorter then posterodorsal seta; mid and hind femora yellow on basal ½-1/3, at least mid and hind tibiae darkened (Figures in Sorokina 2022).—Only North of Russian Far East............................................................. wrangelensis Sorokina

- Scutum with 2 distinct brown narrow longitudinal vittae along dorsocentral setae, without brown dust; mid tibia with long and subequal anterodorsal and posterodorsal setae; mid and hind femora yellow at least on basal 2/3, all tibiae yellow........ 27

27. Fore femur darkened at most on dorsal surface, ventral surface yellow; mid and hind femora only with a small dark dorsal mark (Figures of C. morrisoni in Sorokina 2022).—West Siberia, Far East; Holarctic............ cingulipes (Zetterstedt) (part)

- Fore femur completely black; mid and hind femur with black apical ring........................................ 28

28. Hind tibia with a well-developed submedian posterodorsal seta, as long as 2/3 of anterodorsal seta; cheek higher than width of postpedicel ( Fig. 9G ); sternite 5 small and short, as long as length of sternite 4; cerci short and wide. Larger size: 5.0– 6.8 mm.—Far East; Holarctic................................................................ alaskensis Huckett

- Hind tibia without submedian posterodorsal seta, or with a short weak seta which shorter than anterodorsal seta; cheek not higher than width of postpedicel ( Fig. 4I ); sternite 5 large, as long as length of sternite 3+4; cerci long and thin. Smaller size: 3.0– 5.5 mm.—European Russia, Siberia, Far East; Holarctic.............................. octopunctata (Zetterstedt)

29. Mid femur in apical third without a strong anterior preapical seta.............................................. 30

- Mid femur in apical third with a strong anterior preapical seta................................................. 34

30. Body entirely yellow; scutum densely grey dusted, pleura yellow with a grey dusted spot on anepimeron; apical tarsomeres of all legs blackish, hind tibia with 4 long and thin posteroventrals in apical third.—Only Russian Far East (Kunashir Island).......................................................................................... polina Vikhrev

- At least thorax and abdomen grey, not yellow.............................................................. 31

31. Antenna and palpus partly or completely yellow; scutum brownish dusted, without dark longitudinal stripes (Figures in Vikhrev & Sorokina 2018).—West Siberia, Far East; Holarctic.......................................... demoralis Huckett

- Antenna and palpus wholly dark; scutum with brownish longitudinal stripes...................................... 32

32. Scutum with thick brown dust between dc which reaches the apex of scutellum; abdomen with brown rectangular marks on tergites 1+2–5 which merge in two stripes; mid femur with apical posteroventral seta; two proepisternals (Figures in Sorokina 2022).—Only North of Russian Far East................................................... koni Sorokina (part)

- Scutum with 2–3 more or less distinct longitudinal stripes, without brown dust between dc; abdomen with small rounded spots on tergites 1+2–5, sometimes indistinct; mid femur without apical posteroventral seta; usually one proepisternal......... 33

33. Scutum with two distinct brown longitudinal stripes; height of gena 1.3–1.5 times width of postpedicel; mid tibia with short anterodorsal seta, which is half as long as posterodorsal seta.—European Russia, Siberia, Far East; Eurasian.......................................................................................... bilineella (Zetterstedt) (part)

- Scutum with three indistinct brownish longitudinal stripes; height of gena 2.0–2.5 times width of postpedicel ( Fig. 10G ); mid tibia with long anterodorsal seta, which is 2 times as long as posterodorsal seta. Terminalia in Figs 3H, I .—Siberia, Far East; Holarctic......................................................................... conflicta Huckett (part)

34. Antenna and palpus wholly dark; mid tibia with 1 anterodorsal seta. Larger size: 5–6 mm ........................... 35

- Antenna and palpus partly or completely yellow; mid tibia without anterodorsal seta. Smaller size: 3–5 mm ............ 36

35. Abdomen slender, elongate, cylindrical, with a pair of narrow oblong marks on tergites 1+2–5; cheek always higher than width of postpedicel ( Fig. 10A ).—Siberia, Far East; Holarctic................................. baicalensis (Schnabl) (part)

- Abdomen stout and conical, with a pair of triangular spots on tergites 1+2–5; cheek higher or not than width of postpedicel; mid and hind femur only with small dark dorsal mark (Figures to C. morrisoni in Sorokina 2022).—West Siberia, Far East; Holarctic.................................................................... cingulipes (Zetterstedt) (part)

36. Postpronotal lobe and greater part of pleura yellow, abdomen yellow with dark spots on tergites 3–5 (sometimes only on tergite 4). Terminalia in Figs 3 F, G .—Only South of Russian Far East................................... ghilarovi Lobanov

- Postpronotal lobe and all pleura gray, abdomen yellow or mostly grey.......................................... 37

37. Palpus at least broadly yellow at tip, usually almost or completely yellow; tip of antennal pedicel yellow; dark dorsocentral vittae weakly visible; sternite 5 with setae and setulae long and dense.—European Russia, Siberia, Far East; Holarctic, Oriental........................................................................................ mollicula (Fallén)

- Palpus wholly dark or at least dark at tip; antennal pedicel and flagellomere usually narrowly reddish basally; dark dorsocentral vittae conspicuous and strongly marked; sternite 5 with setae and setulae shorter and sparser.—Siberia, Far East; Eurasian....................................................................................... alpicola (Pokorny)

38. Postpedicel with a spine-like dorsal tip ( Fig. 9D )........................................................... 39

- Postpedicel without a spine-like dorsal tip, rounded at tip..................................................... 44

39. Sternite 5 with dense long yellow setae; antenna and vibrissa completely yellow ( Fig. 9E ).—Only Siberia and Mongolia; Asian................................................................................. kosterini Vikhrev

- Sternite 5 without dense long yellow setae; antenna and vibrissa dark........................................... 40

40. All femora completely reddish-yellow.—European Russia, Siberia; Eurasian........................ ambulans Meigen

- Femora at least partly black............................................................................ 41

41. Legs black, at most knees pale.......................................................................... 42

- At least mid and hind femora pale basally................................................................. 43

42. Body uniformly whitish-blue dusted; frontal vitta thrice as wide as fronto-orbital plate; postpedicel not reaching to the level of oral margin; height of gena equal to width of postpedicel.—European Russia; European........... flavimana (Zetterstedt)

- Body whitish-grey, with a dark pattern; frontal vitta twice as wide as fronto-orbital plate; postpedicel long, reaching to the level of oral margin; height of gena 1.5–2.0 times width of postpedicel ( Fig. 1A ). Terminalia in Figs 1 D–F .—Only North of Russian Far East (Magadan)......................................................................... luxia sp. nov.

43. Femora predominantly yellow: fore femur with dark dorsal streak, mid and hind femora with darkened apical third.—European Russia; European........................................................................ acuminata Strobl

- Fore femora predominantly dark, mid and hind femora usually darkened in distal halves or more.—European Russia, Siberia, Far East; Holarctic.................................................................. pulicaria (Zetterstedt)

44. Only one proepisternal seta (sometimes with an additional weak seta on one side)................................. 45

- Two proepisternals................................................................................... 51

45. Mid tibia with 1 strong anterodorsal seta.................................................................. 46

- Mid tibia without an anterodorsal seta.................................................................... 48

46. Scutum with two distinct brown longitudinal stripes; postpedicel ca. 4 times as long as wide; mid tibia of male with a short anterodorsal seta, which is half as long as posterodorsal seta; pulvilli elongate.—European Russia, Siberia, Far East; Eurasian............................................................................ bilineella (Zetterstedt) (part)

- Scutum without or with three indistinct brownish longitudinal stripes; postpedicel ca. 2.0–3.0 times as long as wide; mid tibia of male with a long anterodorsal seta, which is 2 times as long as posterodorsal seta; pulvilli small.................... 47

47. Height of gena 2.0–2.5 times width of postpedicel; antenna black or postpedicel brown at base ( Fig. 10G ).—Siberia, Far East; Holarctic......................................................................... conflicta Huckett (part)

- Height of gena less than 2 times width of postpedicel; postpedicel yellow on basal half, pedicel yellow at apex.—Far East; Holarctic......................................................................... incisurata van der Wulp

48. Frons wide, at middle 0.5 of head-width at this point; frontal vitta and fronto-orbital plate velvety black; scutum and scutellum densely brown dusted; postpedicel black, long, ca. 3.5 times as long as wide and almost reaching mouth-edge (Figures in Sorokina 2022). Smaller size: 2.1–2.2 mm.—Only Siberia and Russian Far East...................... adriani Sorokina

- Frons narrower; frontal vitta and a fronto-orbital plate not velvety black, grey; scutum and scutellum without dense brown dust, grey with brownish stripes; postpedicel black or reddish at base, small, not reaching mouth-edge. Larger size: 2.5–5.0 mm... .................................................................................................. 49

49. Posterior and posteroventral setulae on fore tarsomeres elongate and semi-erect, longer than depth of tarsus; mid femur usually with 2 preapical posterodorsals and 3-4 strong posteroventrals in basal 2/3.—European Russia; European.................................................................................................... nigridigita Rondani

- Posterior and posteroventral setulae on fore tarsomeres short, decumbent; setae on mid femur different................ 50

50. Hind femur with one or more well developed posteroventral setae on apical half; postpedicel more or less yellowish.—European Russia, Siberia, Far East; Eurasian.......................................................... rufipalpis Meigen

- Hind femur with distinct posteroventrals on basal half only; postpedicel black.—European Russia, Siberia; Palaearctic................................................................................. testacea (Robineau-Desvoidy)

51. All femora black, only narrowly yellow apically............................................................ 52

- Femora at least partly yellow........................................................................... 56

52. Tibiae light yellow to reddish-yellow; sternite 5 projecting ventrally from abdomen at an angle of about 45º; hind femur with 2–3 long anteroventral setae and with 1 long posteroventral seta at middle.—European Russia, Siberia; Palaearctic..................................................................................... Macrorchis meditata (Fallén)

- Tibiae dark yellow to brownish or darkened to almost black, only yellow on basal third; sternite 5 normal, not projecting ventrally below abdomen; hind femur with more or less full rows of anteroventrals and posteroventrals................ 53

53. Hind tibia without submedian posterodorsal seta; only one pair of presutural dorsocentrals.......................... 54

- Hind tibia with submedian posterodorsal; two pair of presutural dorsocentrals.................................... 55

54. Abdomen short, ovate, enlarged dorso-ventrally ( Fig. 4A ); mid tibia with anterodorsal seta. Terminalia in Figs 5 A–C .— European Russia; European............................................................ nevadensis Lyneborg

- Abdomen slender and long, nearly parallel-sided ( Fig. 4G ); mid tibia usually without anterodorsal seta.—European Russia; European............................................................................ octosignata Rondani

55. Scutum with 3 distinct brown longitudinal vittae; lower calypter much longer than upper one; usually calypters white ( Fig. 8D ). Terminalia in Fig. 5 D .—Only West Siberia and Russian Far East................................ nigrotincta Hennig

- Scutum with 2 very diffuse brownish longitudinal vittae; lower calypter scarcely longer than upper one; usually calypters yellow ( Figs 7H , 8E ). Terminalia in Figs 5 E, F .—Only West Siberia and Russian Far East...... ukokensis Sorokina (part)

56. Fore femur predominantly dark......................................................................... 57

- Fore femur predominantly yellow or at most with a dark dorsal streak or spot..................................... 68

57. Two pairs of presutural dorsocentral setae, the anterior pair about half as long as posterior pair....................... 58

- Only one pair of presutural dorsocentrals................................................................. 62

58 Smaller size: 2.8–3.0 mm. Hind tibia black; hind tarsi thickened, all segments about twice as wide as those of mid tarsus; fore tarsomeres 1–4 yellow, tarsomere 5 black ( Fig. 11A ).—Far East; Holarctic..................... atritibia Ringdahl (part)

- Larger size: 4.2–6.2. Hind tibia yellow; hind tarsomeres slender, mostly as wide as mid tarsomeres................... 59

59. Hind femur only in distal third with 2–3 long anteroventral setae, long posteroventral setae only in basal third; mid and hind femora predominantly yellow, only with a weak brownish subapical ring.—Only Siberia and Russian Far East.............................................................................................. sibirica Hennig (part)

- Hind femur with full rows of long and strong anteroventrals and posteroventrals; mid and hind femora black at least in distal ½ or 1/3.............................................................................................. 60

60. Mid and hind femora mainly black, with yellow only basal 1/4 or 1/3; mid tibia without strong posterodorsal setae; abdomen short, as long as thorax; sternites II–IV strongly shortened, together shorter than sternite V. Body length 4.5 mm.—West Siberia; Holarctic............................................................................... comita (Huckett)

- Mid and hind femora yellow at least in basal half; mid tibia with strong or without hair-like posterodorsal seta; abdomen oblong, longer than thorax; sternites II–IV not shortened, together longer than sternite V. Body length 5.0– 6.2 mm ....... 61

61. Hind tibia without strong or with hair-like posterodorsal setae in middle; mid and hind femora yellow in basal ½ or 2/3; antenna occupying 2/3 of height of face ( Fig. 11C ); epandrium without apical process. Terminalia in Fig. 5 G .—Only Siberia and Russian Far East....................................................................... apukaensis Hennig

- Hind tibia with 1 or 2 strong posterodorsal setae in middle; mid and hind femora yellow in basal 2/3 or 3/4; antenna occupying 3/4 of height of face ( Fig. 11F ); epandrium with apical process. Terminalia in Fig. 5 H .—Only Russian Far East and China; Asian.................................................................................... xuei Cui et Li

62. Sternite 5 very large, projecting ventrally from abdomen, with coarse recurved setae (Figures in Sorokina 2022).—Only West Siberia.............................................................................. tschernovi Sorokina

- Sternite 5 small, not projecting ventrally from abdomen, without coarse setae..................................... 63

63. Sternite 5 with long and fine hairs; hind femur without anteroventral and posteroventral setae, but with long and fine hairs on their place.—European Russia; European................................................ dubiosa Hennig (part)

- Sternite 5 without long and fine hairs; at least 1 or 2 strong anteroventral and posteroventral setae and with only a few fine hairs near base on hind femur.............................................................................. 64

64. Hind tibia black; hind tarsomeres thickened, all segments about twice as wide as those of mid leg; fore tarsomeres 1–4 yellow, tarsomere 5 contrastingly black ( Fig. 11A ).—Far East; Holarctic............................. atritibia Ringdahl (part)

- Hind tibia yellow or brown; hind tarsomeres slender, mostly as wide as those of mid leg; fore tarsus with at least tarsomeres 3–5 darkened....................................................................................... 65

65. Scutum with 3 distinct brown narrow longitudinal vittae along dorsocentral and acrostichal setae, with brown dust between dorsocentral setae, reaching the apex of scutellum; mid femur with apical posteroventral setae; gena higher than width of postpedicel, 2 times as long as postpedicel; mid and hind femora usually yellow on basal 1/3 (Figures in Sorokina 2022).—Only North of Russian Far East........................................................ wrangelensis Sorokina (part)

- Scutum without distinct longitudinal vittae and brown dust between dorsocentral setae, scutellum grey; mid femur without apical posteroventral setae; gena not higher than width of postpedicel; mid and hind femora yellow at least on basal 2/3... 66

66. All tarsomeres black; mid femur in apical third with preapical anterior seta; cerci thin and long.—European Russia; European.......................................................................... femoralis (Robineau-Desvoidy)

- At least fore basitarsus yellowish; mid femur in apical third without preapical anterior seta; cerci not long, wide......... 67

67. Only last tarsomere of fore leg black; mid femur entirely yellow; hind femur darkened at apex.—European Russia, Siberia, Far East; Eurasian....................................................................... pygmaea (Zetterstedt)

- Apical darkening of fore tarsus not confined to last tarsomere; mid femur with indistinct and hind femur with distinct subapical dark ring.—European Russia, Siberia, Far East; Holarctic.......................................... verralli Collin

68. Postpedicel yellow at least basally....................................................................... 69

- Antenna entirely black................................................................................ 71

69. Hind tibia with long and strong submedian posterodorsal seta.—European Russia, Siberia, Far East; Eurasian................................................................................................. flavicornis (Fallén)

- Hind tibia without long and strong submedian posterodorsal seta............................................... 70

70. Mid tibia with anterodorsal seta; anteroventral seta on hind tibia in a normal, truly anteroventral position; abdomen at least basally more or less yellow; parafacial reaching about ½ width of postpedicel.—Siberia; Eurasian....................................................................................................... ruficornis (Macquart)

- Mid tibia without anterodorsal seta; long and fine anteroventral seta on hind tibia in strictly ventral position; abdomen entirely dark; parafacial narrow, reaching about 1/3 width of postpedicel.—European Russia; European........... pudorosa Collin

71. Apical scutellar setae distinctly shorter and weaker than basal scutellars......................................... 72

- Apical and basal scutellars subequal in length.............................................................. 73

72. Axillary lobe of wing less developed, wing uniformly narrowed from about apical third to base; mouth-edge projecting slightly beyond level of profrons.—European Russia, Siberia; Holarctic.................................... pedella (Fallén)

- Axillary lobe of wing developed normally; mouth-edge not projecting beyond level of profrons.—Only Siberia, Russian Far East and China; Asian................................................................. griseiventris Ringdahl

73. Hind tibia with submedian posterodorsal seta.............................................................. 74

- Hind tibia without submedian posterodorsal seta............................................................ 77

74. Sternite 5 with long and dense hairs; fore tibia with anterodorsal seta in distal half; mid femur in distal third without long posteroventral setae.—European Russia, Siberia; Eurasian................................... trilineella (Zetterstedt)

- Sternite 5 with conspicuously shorter hairs; fore tibia without anterodorsal seta in distal half or with a very weak one on fore tibia; mid femur in distal third with strong posteroventrals.................................................... 75

75. Postpedicel long, about 5.0 times as long as wide, reaching mouth-edge; parafacial very narrow, much narrower than width of postpedicel; hind femur with brown dorsal streak; abdomen without distinct spots; arista short pubescent; sternite 5 narrower. Terminalia in Figs 13 A, B .—Caucasus; European............................................ emiliae Lukasheva

- With a different combination of characters................................................................ 76

76. Posterodorsal seta on hind tibia as long and strong as anterodorsal seta; arista long-haired, the longest individual hairs as long or a little more than half width of postpedicel; abdomen without spots ( Fig. 12A ).—Siberia, Far East; Asian ( China, Japan)........................................................................................ lacustris Schnabl

- Posterodorsal seta on hind tibia half as long as anterodorsal seta or even shorter and hair-like; arista short-haired, the longest individual hairs shorter than half width of postpedicel; abdomen often with dark spots ( Fig. 12C ).—Only Siberia, Far East and China; Asian........................................................................... luteipes Ringdahl

77. Basal half of hind femur with dense hairs on ventral surface.................................................. 78

- Hind femur without dense hairs on ventral surface.......................................................... 79

78. Fore femur with dark dorsal spot; mid and hind femora with long hairs on anterior-posterior surface; mid femur without preapical anterior seta; sternite 5 with long hairs; abdomen oval and plump.—European Russia; European................................................................................................. dubiosa Hennig (part)

- Fore femur completely yellow; mid femur only with 3 strong posteroventral setae on basal half, with preapical anterior seta; hind femur with short hairs on basal half of ventral surface; sternite 5 without long hairs; abdomen not plump, elongated.— European Russia, Siberia; Eurasian......................................................... perpusilla Meigen

79. All tarsi reddish-yellow, at most middle tarsomeres of fore legs slightly darkened; scutum and scutellum brown dusted; abdomen with more or less distinct paired spots and brown dust between them dorsally; mid femur with a strong anterior and a posterior preapical seta, without posterovental setae at apex, with 1 or 2 weak setae in basal third; mid tibia with antero- and posterodorsal setae the same length and at the same level. Small size: 1.9–2.3 mm.—European Russia, Far East (Magadan); Eurasian................................................................................ paludis Tiensuu

- With a different combination of characters................................................................ 80

80. Mid femur with a preapical anterior seta; all apical tarsomeres yellowish........................................ 81

- Mid femur without a preapical anterior seta; all apical tarsomeres black......................................... 82

81. Sternite 5 as long as length of sternites 4 + 3, with numerous long and fine hairs ( Fig. 12G ); abdomen without distinct spots; mid femur with 3-4 strong and long anteroventral setae which are longer than diameter of femur; hind femur with long anterovenrals and posteroventrals.—Only Russian Far East................................................. pilipyga Ringdahl

- Sternite 5 shorter, as long as sternite 4, without numerous long and fine hairs, only with individual long setae ( Fig. 12H ); abdomen with distinct brown spots; mid femur with 1 or 2 anteroventral setae in basal third; hind femur with short anterovenrals and posteroventrals.—European Russia, Siberia, Far East; Holarctic................................. pumila (Fallén)

82. Mid tibia with anterodorsal seta strong and twice as long as posterodorsal seta.................................... 83

- Mid tibia without anterodorsal seta, but if this seta present it is weak and much shorter than a posterodorsal, the longest anterodorsal and posterodorsal setae equal in length......................................................... 84

83. Pulvilli and claws long; face moderately concave in profile, not long and narrowing below; fore femur often dorsally or even predominantly brown; mid femur with 3–4 long posteroventral setae in basal half. Larger species (4.5–6.0 mm).—European Russia, Siberia; Holarctic..................................................... campestris (Robineau-Desvoidy)

- Pulvilli and claws very small; fore femur completely yellow; face not concave in profile, rather long and narrowing below; mid femur without anteroventrals and with 1 long posteroventral seta in basal half. Smaller species (3.0– 3.3 mm) ( Fig. 10G ). Terminalia in Figs 3 H, I .—Siberia, Far East; Holarctic.................................... conflicta Huckett (part)

84. Mid femur with a row of posteroventral setae, apical seta present; scutum with brown dust between dorsocentral setae, reaching the apex of scutellum. Smaller size: 2.8–3.0 mm............................................................ 85

- Mid femur without posteroventral setae in apical third; scutum and abdomen with different combination of characters. Bigger size: 3.0–5.0 mm..................................................................................... 86

85. Legs yellow; abdomen with brown rectangular marks which merge and seem to form two stripes (Figures in Sorokina 2022).— Only North of Russian Far East.......................................................... koni Sorokina (part)

- Fore femur with dark dorsal streak, mid and hind femora dark in apical half or third; abdomen with indistinct marks in middle of tergites (Figures in Sorokina 2022).—Only North of Russian Far East.......................... gorodkovi Sorokina

86. Postpedicel long, 3.5–4 times as long as wide; scutum without distinct longitudinal stripes; frontal triangle reaching the anterior margin of frons; palpus brownish-yellow on basal half, darker at apex.—Far East (Kamchatka); Oriental and Asian.......................................................................................... mandschurica Hennig

- Postpedicel not more than 2.5 times as long as wide; scutum with or without distinct longitudinal stripes; frontal triangle reaching or not reaching the anterior margin of frons; palpus brown to black..................................... 87

87. Hind femur with 2–3 strong long anteroventral setae in distal half only and with row of short setae in proximal part; sternite 5 with a wide semicircular median notch, inner edge with numerous short hair-like setae, caudal margin with short setae, pointed ( Fig. 12E ).—Only Siberia and Russian Far East............................................ sibirica Hennig (part)

- Hind femur with 3–4 strong long anteroventral setae in basal, middle and apical parts; sternite 5 with a large rectangular median notch, inner edge without numerous short hair-like setae, caudal margin with long setae which are at least as long as sternite 5, rounded ( Fig. 12F )................................................................................... 88

88. Scutum with 3 distinct brown longitudinal stripes. Terminalia in Fig. 13 C, D .—Only Russian Far East and China; Asian........................................................................................... striolata Hennig

- Scutum without distinct longitudinal stripes, or with 2 indistinct stripes......................................... 89

89. Frontal triangle very narrow and whitish grey distally, reaching anterior margin of frons; cercal plate very slender, at least 6.0 times longer than broad. Terminalia in Fig. 13 E, F .—European Russia, West Siberia; Palaearctic........ albicornis Meigen

- Frontal triangle gradually narrowed distally, not reaching anterior margin of frons; cercal plate broad, about 3.0 times longer than broad. Terminalia in Fig. 13 G, H .—European Russia, Siberia, Far East; Eurasian............ lineatipes (Zetterstedt)

Key to females

The females of C. flavissima , C. kosterini , C. rhaensis , C. sibirica and C. striolata are not known, but the last two species are included in the key according to the characters of the males.

1. Costa extending only to, or very slightly beyond, apex of R 4+5 .................................................. 2

- Costa extending to apex of M 1........................................................................... 3

2. Lower calypter not longer than upper one. Postpedicel with a spine-like dorsal tip.................. connectens (Hennig)

- Lower calypter much longer than upper one. Postpedicel without a spine-like dorsal tip, with a more or less rounded tip........................................................................................ agromyzina (Fallén)

3. Hind tibia with a median anterior seta and an anterodorsal seta at almost the same level and close together ( Fig. 9A )....... 4

- Hind tibia without an anterior seta at middle close to the anterodorsal seta, but an anteroventral seta present............. 9

4. Scutum, scutellum and abdomen shining black.................................................... atra (Meigen)

- Scutum, scutellum and abdomen not shining black........................................................... 5

5. Parafacial at least as broad as postpedicel; longest aristal hairs at least as long as width of postpedicel; outer vertical setae longer and stronger than postocular setulae......................................................... tigrina (Fabricius)

- Parafacial narrower than width of postpedicel; longest aristal hairs much shorter than width of postpedicel; outer vertical setae at most as long as postocular setulae...................................................................... 7

7. All femora yellow, more or less darkened in apical third; abdomen with a midline and paired brown spots.... strigipes Stein

- All femora dark, at most the tips narrowly yellow; abdomen with or without paired spots............................ 8

8. Longest aristal hairs barely longer than basal width of arista; abdomen at most with indistinct pattern.—European Russia........................................................................................... attenuata Stein

- Longest aristal hairs at least half as long as width of flagellomere; abdomen with paired round spots....... humilis Meigen

9. Hind tibia with strong and long preapical dorsal and posterodorsal setae close to each other ( Fig. 9B ).................. 10

- Hind tibia without strong and long, closely approximated preapical dorsal and posterodorsal setae.................... 11

10. Mid and hind femora and all tibiae predominantly yellow...................................... intermedia (Fallén)

- Mid and hind femora and all tibiae predominantly dark but fore and mid trochanters yellow, hind trochanter sometimes darker.—European Russia................................................................... means Meigen

11. Head almost square in lateral view ( Fig. 10F ); frons reddish at antenna, postpedicel black, very long, 4 times as long as wide; oral vibrissae usually yellow or golden but sometimes black...................................... flaviseta Huckett

- With a different combination of characters................................................................ 12

12. Lower calypter shorter than the upper one................................................................. 13

- Lower calypter similar to or longer than upper one.......................................................... 16

13. Basal scutellar setae reduced, apical setae weak and short ( Fig. 7B )................................... ciliata Hennig

- Both pairs of scutellars strong and long................................................................... 14

14. Larger size: 6–7.5 mm ( Fig. 10B ). Mid and find femora completely yellow; mid femur with a strong anterior preapical seta............................................................................... baicalensis Schnabl (part)

- Smaller size: 3.5–5.5 mm. Mid and find femora completely or partially dark; mid femur without a strong anterior preapical seta............................................................................................... 15

15. At least tibiae yellow ( Fig. 10C ); palpus at least yellow on basal half; lower calypter extremely small, shorter than half length of the upper one, strip-like; legs without hairs on ventral surface; preapical anterodorsal and posterodorsal setae on hind tibia indistinct or absent....................................................................... tendipes Huckett

- All tibiae black, only knees yellowish; palpus black; lower calypter as broad as half length of the upper one; legs with hairs on ventral surface; preapical anterodorsal seta on hind tibia long and strong............................ penicillata Hennig

16. Lower calypter subequal in length or scarcely longer than upper one............................................ 17

- Lower calypter much longer than upper one............................................................... 34

17. All femora black, at most with apices narrowly yellow....................................................... 18

- At least mid and hind femora yellow on basal 1/3........................................................... 25

18. Antenna including both basal segments yellow or at least basal segments and base of postpedicel yellowish................................................................................................. dealbata (Zetterstedt)

- Antenna entirely black................................................................................ 19

19. All tibiae predominantly black, at most yellow in basal third.................................................. 20

- All tibiae yellow or brownish-yellow..................................................................... 23

20. Mid femur with a strong distinct anterior preapical seta; scutum with 2 distinct brown narrow longitudinal vittae along dorsocentral setae; scutellum grey, sometimes like scutum with yellowish dust ( Fig. 7E )........... subgracilis Xue & Cui

- Mid femur without anterior preapical seta or with indistinct short seta; scutum with brown dust between dorsocentral setae, reaching the apex of scutellum or completely brown dusted................................................... 21

21. Gena and parafacial broad, height of gena 2 times width of postpedicel, width of parafacial about as wide as postpedicel; mid femur usually with apical posteroventral seta (Figures in Sorokina 2022).................. wrangelensis Sorokina (part)

- Height of gena 1.5–1.7 times width of postpedicel, width of parafacial at middle as wide as ½ or 2/3 of width of postpedicel; mid femur without apical posteroventral seta.............................................................. 22

22. Scutum completely brown dusted; hind femur with a row of short anteroventral setae (Figures in Sorokina 2022)................................................................................................. galina Sorokina

- Scutum with thick brown dust between dc which reaches the apex of scutellum; hind femur with two long anteroventral setae, which are much longer then diameter of femur in distal part and with two anteroventral setae in proximal part of femur (Figures in Sorokina 2022)..................................................................... koni Sorokina (part)

23. Mid femur without a strong anterior preapical seta; preapical anterodorsal and posterodorsal setae on hind tibia distinct, each half as long as preapical dorsal seta. Smaller species (3.5–4.7 mm) ( Fig. 10H ).................. conflicta Huckett (part)

- Mid femur with a strong anterior preapical seta; preapical anterodorsal on hind tibia much longer and stronger than posterodorsal setae. Larger species (5.0– 6.5 mm)...................................................................... 24

24. All tibiae yellow; abdomen with rounded spots; mid femur with a full row of anteroventral setae ( Fig. 7G )....................................................................................................... oralis Schnabl

- All tibiae brownish-yellow, darkened in apical 2/3–4/5; abdomen with more or less triangular spots; mid femur with 5–6 anteroventrals in basal half ( Figs 7I , 8F ).............................................. ukokensis Sorokina (part)

25. Mid femur in apical third without a strong anterior preapical seta.............................................. 26

- Mid femur with a strong anterior preapical seta............................................................. 28

26. Body entirely yellow; scutum densely grey dusted, pleura yellow with grey dusted spot on anepimeron; apical tarsomeres of all legs often blackish.—Far East (Kunashir Island)................................................. polina Vikhrev

- Al least thorax and abdomen grey, not yellow.............................................................. 27

27. Scutum with two distinct brown longitudinal stripes; antenna and palpus wholly dark; fore femur dark, mid and hind femora yellow or with dark dorsal streak.................................................. bilineella (Zetterstedt) (part)

- Scutum brownish dusted, without dark longitudinal stripes; at least base of postpedicel yellow; palpus partly yellow or brownish; all femora yellow or fulvous............................................................... demoralis Huckett

28. Fore femur mostly black, mid and hind femora black or fuscous in dorsal part at apex; antenna completely black........ 29

- All femora completely yellow, at most fore femur with dark dorsal steak; antenna at least yellow at base on ventral surface (except black in C. baicalensis )......................................................................... 31

29. Fore femur darkened at most on dorsal surface, ventral surface yellow; mid and hind femora largely yellow on distal half with a dark mark at most confined to dorsal half of femur; mid femur with 1 preapical posterior seta.... cingulipes (Zetterstedt)

- Fore femur completely black; mid and hind femora with a black apical ring; mid femur with 2 preapical posterior setae... 30

30. Hind tibia with a well-developed posterodorsal seta, as long as 2/3 of anterodorsal seta; gena higher than width of postpedicel ( Fig. 9F )............................................................................. alaskensis Huckett

- Hind tibia without posterodorsal seta, or with some a weak and short seta which shorter than anterodorsal seta; gena not higher than width of postpedicel.......................................................... octopunctata (Zetterstedt)

31. Antenna and palpus wholly dark; mid and hind femora with complete but sparse rows of long posteroventral setae; height of gena 1.5 times width of postpedicel ( Fig. 10B ). Larger size: 6–7.5 mm ...................... baicalensis Schnabl (part)

- Antenna and palpus partly or completely yellow; mid and hind femora with long posteroventrals only in basal half; height of gena at most as wide as width of postpedicel. Smaller size: 3–5 mm ............................................ 32

32. Postpronotal lobe, abdomen and at least katepisterna yellow..................................... ghilarovi Lobanov

- Thorax completely grey, abdomen yellow only at base....................................................... 33

33. Tip of antennal pedicel yellow; palpus at least broadly yellow at tip, usually almost or completely yellow; dark dorsocentral vittae weakly visible; fore femur wholly yellow............................................... mollicula (Fallén)

- Antennal pedicel and postpedicel usually narrowly reddish basally; palpus wholly dark or at least dark at tip; dark dorsocentral vittae conspicuous and strongly marked; fore femur yellow or with a dark dorsal steak............... alpicola (Pokorny)

34. Postpedicel with a spine-like dorsal tip ( Fig. 9D )........................................................... 35

- Postpedicel without a spine-like dorsal tip, rounded at tip..................................................... 38

35. Mid and hind femora yellow but darkened apically............................................. ambulans Meigen

- Mid and hind femora predominantly black................................................................ 36

36. Height of gena 1.5–1.8 times width of postpedicel ( Fig. 1C ); legs completely black, grey dusted like pleura; two proepisternal setae..................................................................................... luxia sp. nov.

- Height of gena less than 1.5 times width of postpedicel, usually as high as wide of postpedicel; at least knees and base of fore and mid tibiae yellow; usually one proepisternal setae....................................................... 37

37. Frons uniformly silvery; abdominal spots brown, well defined................................ flavimana (Zetterstedt)

- Frontal vitta darker than fronto-orbital plates; abdominal spots indistinct........................................................................................... pulicaria (Zetterstedt) & acuminata Strobl (European Russia)

38. Only one proepisternal seta (sometimes with an additional weak seta on one side)................................. 39

- Two proepisternal setae............................................................................... 45

39. All femora black, at most only narrowly yellow apically..................................................... 40

- Femora completely yellow or yellow in apical third......................................................... 41

40. All tibiae yellow ( Fig. 10H ); scutum grey dusted with 2 or 3 brownish vittae, scutellum grey dusted; frontal vitta brownishgrey dusted, fronto-orbital plate silvery-grey dusted; preapical anterodorsal and posterodorsal setae on hind tibia half as long as length of preapical dorsal seta........................................................ conflicta Huckett (part)

- All tibiae black; scutum and scutellum completely densely brown dusted, sometimes with 3 indistinct longitudinal vittae; frontal vitta and a fronto-orbital plate velvety black in frontal view; preapical anterodorsal seta on hind tibia as long as 2/3 length of preapical dorsal seta, preapical posterodorsal absent (Figures in Sorokina 2022)............... adriani Sorokina

41. Postpedicel shorter, ca. 2.2–2.3 times as long as wide. Mid tibia with apical posteroventral seta short, not longer than diameter of tibia where situated.............................................................. incisurata van der Wulp

- Postpedicel longer, ca. 3.0 times as long as wide. Mid tibia with apical posteroventral seta longer or not than diameter of tibia where situated....................................................................................... 42

42. Lower calypter short, little longer than upper one; frontal vitta entirely dark; mid tibia with apical posteroventral seta longer than diameter of tibia where situated............................................... bilineella (Zetterstedt) (part)

- Lower calypter much longer than upper one; anterior margin of frontal vitta reddish-yellow or dark; mid tibia with apical posteroventral seta shorter than or as long as diameter of tibia where situated..................................... 43

43. All coxae yellow; abdomen without or with very indistinct dark paired spots; presutural acrostichal setae weak................................................................................................. rufipalpis Meigen

- Mid and hind coxae partly grey; abdomen with distinct dark paired spots; presutural acrostichals well developed........ 44

44. Anterior margin of frontal vitta reddish-yellow; mid femur with only 1–2 weak posteroventrals in basal 2/3 and mostly with one apical posterodorsal seta; mid tibia with apical posteroventral seta much shorter than diameter of tibia where situated.................................................................................. testacea (Robineau-Desvoidy)

- Anterior margin of frontal vitta usually dark; mid femur with 3–4 posteroventrals in basal 2/3 and usually with 2 apical posterodorsals; mid tibia with apical posteroventral seta ca. as long as diameter of tibia where situated....................................................................................................... nigridigita Rondani

45. Hind tibia with one strong or 3–4 short submedian posterodorsal seta........................................... 46

- Hind tibia without a submedian posterodorsal setae......................................................... 55

46. Middle and hind femora black at least in distal half or entirely black; 2 pairs of strong presutural dorsocentral setae present (except 1 pair in C. ozerovi )............................................................................ 47

- Femora completely or predominantly yellow; only one pair of presutural dorsocentrals............................. 51

47. Middle and hind femora yellow in basal part............................................................... 48

- Middle and hind femora entirely black................................................................... 49

48. Middle and hind femora yellow in basal ½ part ( Fig. 11E ); hind tibia usually with 1 strong posterodorsal seta..................................................................................................... xuei Cui et Li

- Middle and hind femora yellow in basal ¼ or 1/3 ( Fig. 11D ); hind tibia with 3–4 short hair-like posterodorsal setae....................................................................................... apukaensis Hennig (part)

49. One pair of strong presutural dorsocentral setae present; all tibiae black, knees yellow; abdomen without dark spots ( Fig. 8B )....................................................................................... ozerovi Vikhrev

- Two pair of strong presutural dorsocentral setae present; tibiae yellow at least in basal third; abdomen with dark spots on tergites 3–5......................................................................................... 50

50. Scutum with 3 brown longitudinal vittae; lower calypter much longer than upper one; postpedicel 3.5 times as long as wide, nearly reaching vibrissal angle ( Fig. 8C ).................................................... nigrotincta Hennig

- Scutum with 2 brown longitudinal vittae; lower calypter slightly longer than upper one; postpedicel 2.5 times as long as wide, its length about 2/3 height of face ( Figs 7I , 8F )......................................... ukokensis Sorokina (part)

51. Postpedicel yellow basally............................................................... flavicornis (Fallén)

- Postpedicel completely black........................................................................... 52

52. Mid femur in distal third without long posteroventral setae.................................. trilineella (Zetterstedt)

- Mid femur in distal third with strong posteroventrals........................................................ 53

53. Postpedicel long, about 5.0 times as long as wide, reaching the mouth margin; parafacial very narrow, much narrower than width of postpedicel; fore femur with brown dorsal streak; mid and hind femora darkened apically; arista short pubescent....................................................................................... emiliae Lukasheva

- With a different combination of characters................................................................ 54

54. Posterodorsal seta of hind tibia as long and strong as the anterodorsal seta ( Fig. 12B ).................. lacustris Schnabl

- Posterodorsal seta of hind tibia shorter than or even half as long as the anterodorsal ( Fig. 12D ).......... luteipes Ringdahl

55. Apical scutellar setae distinctly shorter and weaker than basal scutellar setae..................................... 56

- Apical and basal scutellars subequal in length.............................................................. 57

56. Mid and hind femora black; mouth margin projecting slightly beyond level of profrons.................. pedella (Fallén)

- Mid and hind femora yellow; mouth margin not projecting beyond level of profrons............... griseiventris Ringdahl

57. Two pairs of presutural dorsocentral setae, anterior pair about 1/3–2/3 as long as posterior pair ( C. apukaensis Hennig sometimes without distinct anterior pair)........................................................................... 58

- Only one pair of presutural dorsocentrals................................................................. 62

58. At least base of postpedicel yellowish; base of abdomen more or less yellow.................... ruficornis (Macquart)

- Antenna entirely black; abdomen entirely grey............................................................. 59

59. At least basal third or quarter of mid and hind femora yellow; hind femur with a full row of strong posteroventrals....................................................................... comita (Huckett) & apukaensis Hennig (part)

- All femora black, only narrowly yellow apically; hind femur with strong posteroventral setae only on basal half......... 60

60. All tibiae yellow. Larger size: 6.0–8.0 mm.......................................... Macrorchis meditata (Fallén)

- At least hind tibia black. Smaller size: 3.5–4.3 mm .......................................................... 61

61. Fore and mid tibiae yellow, hind tibia black; hind tarsi thickened, all segments about twice as wide as those of mid tarsus; height of gena ca. 1.3 times width of postpedicel ( Fig. 11B )...................................... atritibia Ringdahl (part)

- All tibiae black, except yellow basal third or fourth; hind tarsi not thickened; height of gena ca. 2.3–3.0 times width of postpedicel (Figures in Sorokina 2022)......................................................... gorodkovi Sorokina (part)

62. Mid and hind femora predominantly yellow, darkened dorsally at apex.......................................... 63

- Mid and hind femora predominantly black, basal half never entirely yellow...................................... 69

63. Anteroventral seta on hind tibia in strictly ventral position......................................... pudorosa Collin

- Anteroventral seta on hind tibia in a normal, truly anteroventral position......................................... 64

64. Smaller size, the largest 3.5 mm. Mid and hind femora completely yellow or with dark dorsal spot at apex; hind femora with posteroventral setae only in basal half.................................................................... 65

- Larger size, more than 3.5 mm. Mid and hind femora yellow with black rings in apical fourth; hind femora with posteroventral setae in basal 2/3..................................................................................... 66

65. Mid and hind femora completely yellow, without dark dorsal spot at apex........................ mandschurica Hennig

- Mid and hind femora yellow with dark dorsal spot at apex......................................... dubiosa Hennig

66. Postpedicel 3.0 times as long as wide; scutum with 3 dark longitudinal vittae; presutural acrostichals in one irregular row............................................................................ campestris (Robineau-Desvoidy)

- Postpedicel about 2.5 times as long as broad; scutum with 3 distinct or with 2 indistinct longitudinal vittae, mid vitta usually reduced; presutural acrostichals in 2 rows................................................................. 67

67. Frontal triangle reaching anterior margin of frons.............................................. albicornis Meigen

- Frontal triangle not reaching anterior margin of frons........................................................ 68

68. Scutum with 3 distinct brown longitudinal vittae................................. striolata Hennig & sibirica Hennig

- Scutum without distinct longitudinal vittae, or with 2 indistinct stripes......................... lineatipes (Zetterstedt)

69. Mid femur with a strong anterior preapical seta............................................................. 70

- Mid femur without a strong anterior preapical seta.......................................................... 76

70. At least hind tibiae black.............................................................................. 71

- All tibiae yellow..................................................................................... 73

71. Fore and mid tibiae yellow, hind tibia black; hind tarsi thickened, all tarsomeres about twice as wide as those of mid tarsus ( Fig. 11A )............................................................................ atritibia Ringdahl (part)

- All tibiae predominantly black; hind tarsi not thickened...................................................... 72

72. Scutum with distinct brown narrow longitudinal vittae along dorsocentral, acrostichal setae and posthumeral to intra-alar setae, with brown dust between dorsocentral setae, reaching the apex of scutellum; mid femur with a posteroventral seta in apical third (Figures in Sorokina 2022)....................................................... wrangelensis Sorokina (part)

- Scutum with 3 longitudinal vittae along dorsocentral and acrostichal setae but without brown dust between dorsocentral setae, scutellum grey; mid femur without posteroventral seta in apical third. European Russia..... femoralis (Robineau-Desvoidy)

73. Hind femur with a complete row of posteroventral setae; frontal vitta dull black in frontal view......... perpusilla Meigen

- Hind femur with 0–2 posteroventrals in basal half; frontal vitta grey in frontal view................................ 74

74. Hind femur without posteroventrals in basal half................................................ paludis Tiensuu

- Hind femur with 2 posteroventrals in basal half............................................................ 75

75. Mid femur usually with 1 or 2 anteroventral setae in basal third (long and short setae); mid and hind femora usually yellow in basal third; at least tergites 3–5 with pairs of rounded spots and sometimes a vitta between them........... pumila (Fallén)

- Mid femur with 3 or 4 anteroventral setae in basal half or in basal 2/3; mid and hind femora mostly subshining black; abdomen without or with indistinct pairs of spots...................................................... pilipyga Ringdahl

76. Gena narrower than postpedicel; parafacial narrower than anterior ocellus....................... pygmaea (Zetterstedt)

- Gena distinctly broader than postpedicel; parafacial broader than anterior ocellus.................................. 77

77. All tibiae predominantly black, only basally paler........................................................... 78

- At least fore and mid tibiae yellow....................................................................... 82

78. Scutum with 2–3 brown longitudinal vittae, without brown dust between them; abdomen with distinct brown paired spots... .................................................................................................. 79

- Scutum with brown narrow longitudinal vittae along dorsocentral, acrostichal setae and posthumeral to intra-alar setae; with brown dust between dorsocentral setae, reaching the apex of scutellum; abdomen without spots or with small indistinct brownish marks or spots....................................................................................... 80

79. Scutum with 3 distinct brown longitudinal vittae ( Fig. 4E ); abdomen with large brown paired spots ( Figs 4 F, H ).............................................................................................. octosignata Rondani

- Scutum with 2 distinct brown longitudinal vittae and with traces of a weak median vitta between them ( Fig. 4D ); brown oval spots of abdomen smaller and less well-defined ( Figs 4 B, C )................................. nevadensis Lyneborg

80. Height of gena ca. 1.5–1.7 times width of postpedicel; mid femur with 1 preapical posterior seta, without preapical posteroventral seta; abdomen without spots or marks (Figures in Sorokina 2022)............................... koni Sorokina (part)

- Height of gena ca. 2.0–3.0 times width of postpedicel; mid femur with 1 or 2 preapical posterior setae, with or without preapical posteroventral seta; abdomen usually with dark marks, sometimes indistinct...................................... 81

81. Lower calypter a little longer than upper one; abdomen with brown rounded spots, sometimes indistinct (Figures in Sorokina 2022)........................................................................ wrangelensis Sorokina (part)

- Lower calypter much longer than upper one; abdomen with diffuse brown marks reaching ventral surface of tergites (Figures in Sorokina 2022)................................................................ gorodkovi Sorokina (part)

82. All tibiae completely light yellow ( Fig. 10H ); preapical anterodorsal and posterodorsal setae on hind tibia weak but distinct, each half as long as preapical dorsal seta, this seta a little shorter than median anterodorsal seta; lower calypter a little longer than upper one.................................................................... conflicta Huckett (part)

- Tibiae brownish or partly darkened, not light yellow; preapical anterodorsal and dorsal on hind tibia long and strong, the dorsal about as long as median anterodorsal, without a distinct preapical posterodorsal; lower calypter much longer than upper one. .................................................................................................. 83

83. All trochanters greyish-brown; abdomen with rounded spots, sometimes indistinct; scutum without distinct dorsocentral vittae; hind tibia mostly brownish; postpedicel rounded at apex........................................... verralli Collin

- At least fore and mid trochanters yellow; abdomen usually without spots; scutum with three longitudinal vittae; hind tibia with a dark ring in basal and apical third; postpedicel pointed at apex (Figures in Sorokina 2022).......... tschernovi Sorokina

Figures

FIGURE 1. Coenosia luxia sp. nov. A. Holotype, male, lateral view. B. Holotype, dorsal view. C. Paratype, female, lateral view. D. Terminalia, lateral view. E. Cercal plate, dorsal view. F. Sternite 5. Bare: 1 mm.

FIGURE 3. Coenosia spp. A–C. Coenosia ozerovi. A. Terminalia, lateral view. B. Cercal plate, dorsal view. C. Sternite 5. D, E. Coenosia subgracilis. D. Terminalia, lateral view. E. Cercal plate, dorsal view. F, G. Coenosia ghilarovi (from Lobanov, 1988). F. Terminalia, lateral view. G. Cercal plate, dorsal view. H, I. Coenosia conflicta. H. Terminalia, lateral view. I. Cercal plate, dorsal view.

FIGURE 4. Coenosia spp. A–D. Coenosia nevaedensis. A. Male habitus, lateral view. B. Female habitus, lateral view. C. Female abdomen, dorsal view. D. Female scutum, dorsal view. E–H. Coenosia octosignata. E. Female scutum, dorsal view. F. Female abdomen, dorsal view. G. Male habitus, lateral view. H. Female habitus, lateral view. I. Coenosia octopunctata, male habitus, lateral view. Bare: 1 mm.

FIGURE 5. Coenosia spp. A–C. Coenosia nevaedensis. A. Terminalia, lateral view. B. Cercal plate, dorsal view. C. Sternite 5. D. Coenosia nigrotincta, terminalia, lateral view. E, F. Coenosia ukokensis. E. Terminalia, lateral view. F. Cercal plate, dorsal view. G. Coenosia apukaensis, terminalia, lateral view. H. Coenosia xuei, terminalia, lateral view.

FIGURE 6. Coenosia spp. A–E. Coenosia penicillata. A. Terminalia, lateral view. B. Cercal plate, dorsal view. C. Sternite 5. D. Terminalia, lateral view (from Shinonaga, 2003). E. Sternite 5 (from Shinonaga, 2003). F, G. Coenosia oralis. F. Terminalia, lateral view. G. Cercal plate, dorsal view. H, I. Coenosia tendipes. H. Terminalia, lateral view. I. Cercal plate, dorsal view.

FIGURE 7. Coenosia spp. A, B. Coenosia ciliata. A. Male habitus, lateral view. B. Female habitus, lateral view. C. Coenosia penicillata, male habitus, lateral view. D, E. Coenosia subgracilis. D. Male habitus, lateral view (the holotype of Coenosia altaica Sorokina, 2009). E. Female habitus, lateral view (the paratype of C. altaica Sorokina, 2009). F, G. Coenosia oralis. F. Male habitus, lateral view. G. Female habitus, lateral view; H, I. Coenosia ukokensis. H. Male, holotype, lateral view. I. Female, paratype, lateral view. Bare: 1 mm.

FIGURE 8. Coenosia spp. A, B. Coenosia ozerovi. A. Male habitus, lateral view. B. Female habitus, lateral view. C, D. Coenosia nigrotincta. C. Female habitus, lateral view (Pevek). D. Male habitus, lateral view (Beringovskii). E, F. Coenosia ukokensis. E. Male habitus, lateral view (Magadan). F. Female habitus, lateral view (Magadan). Bare: 1 mm.

FIGURE 9. Coenosia spp. A. Coenosia tigrina, female, hind tibia. B. Coenosia intermedia, female, hind tibiae. C. Coenosia ozerovi, male, fore tarsi. D. Coenosia ambulans, female, head. E. Coenosia kosterini, male, lateral view. F, G. Coenosia alaskensis. F. Female habitus, lateral view. G. Male habitus, lateral view. Bare: 1 mm.

FIGURE 10. Coenosia spp. A, B. Coenosia baikalensis. A. Male habitus, lateral view. B. Female habitus, lateral view. C, D. Coenosia tendipes. C. Female habitus, lateral view. D. Male habitus, lateral view. E, F. Coenosia flaviseta. E. Male, head, lateral view. F. Female habitus, lateral view. G, H. Coenosia conflicta. G. Male habitus, lateral view. H. Female habitus, lateral view. Bare: 1 mm.

FIGURE 11. Coenosia spp. A, B. Coenosia atritibia. A. Male habitus, lateral view. B. Female habitus, lateral view. C, D. Coenosia apukaensis. C. Male habitus, lateral view. D. Female habitus, lateral view. E, F. Coenosia xuei. E. Female habitus, lateral view. F. Male habitus, lateral view. Bare: 1 mm.

FIGURE 12. Coenosia spp. A, B. Coenosia lacustris. A. Male habitus, lateral view. B. Female habitus, lateral view. C, D. Coenosia luteipes. C. Male habitus, lateral view. D. Female habitus, lateral view. E. Coenosia sibirica, male abdomen, ventral view. F. Coenosia lineatipes, male sternite 5, ventral view. G. Coenosia pilipyga, male abdomen, lateral view. H. Coenosia pumila, male abdomen, lateral view. Bare: 1 mm.

FIGURE 13. Coenosia spp. A, B. Coenosia emilia (from Lukasheva, 1986). A. Terminalia, lateral view. B Cercal plate, dorsal view. C, D. Coenosia striolata (from Hennig, 1961b, 1962). C. Terminalia, lateral view. D. Cercal plate, dorsal view. E, F. Coenosia albicornis (from Hennig, 1961b, 1962). E. Terminalia, lateral view. F. Cercal plate, dorsal view. G, H. Coenosia lineatipes (from Hennig, 1961b, 1962). G. Terminalia, lateral view. H. Cercal plate, dorsal view.