Bombus

An, Jiandong, Huang, Jiaxing, Shao, Youquan, Zhang, Shiwen, Wang, Biao, Liu, Xinyu, Wu, Jie & Williams, Paul H., 2014, The bumblebees of North China (Apidae, Bombus Latreille), Zootaxa 3830 (1), pp. 1-89 : 11-15

Key to the species of the genus Bombus known from North China for females:

1 Hind tibia with the outer surface broad, almost flat, most of the outer surface in the distal half without moderate to long hairs, but fringed with stout hairs that form a pollen basket (corbicula), the inner distal margin with a comb of stout spines (rastellum); S6 without ventro-lateral keels..................................................................... 2

- Hind tibia with the outer surface strongly and uniformly convex and uniformly densely covered with moderate to long stout hairs throughout, the fringing hairs often poorly differentiated and not forming a pollen basket (corbicula), the inner distal margin without a comb of stout spines (rastellum); S6 with ventro-lateral keels..............................45 Psithyrus

2 (1) Mandible with the anterior keel reaching and continuous with the distal margin; the labrum with a longitudinal median furrow and a ventral transverse lamella; hindleg tibia outer surface smooth, shiny and with at most with one or two stout long hairs near the centre in the proximal half....................................................................... 3

- Mandible with the anterior keel not reaching and separated from the distal margin; the labrum lacks a distinct longitudinal median furrow and ventral transverse lamella; hindleg tibia outer surface rough, matte and with many widely spaced stout long hairs near the centre in the proximal half....................................................10 Mendacibombus

3 (2) Mandible distally broadly rounded, with two anterior teeth and often a posterior tooth; hindleg basitarsus with the longest erect hairs near the anterior margin of the outer surface as long as or usually shorter than the narrowest breadth of the basitarsus. 4

- Mandible distally not broadly rounded, but with six evenly-spaced large triangular teeth (which may become worn down); hindleg basitarsus with the longest erect hairs near the anterior margin of the outer surface as long or longer than the narrowest breadth of the basitarsus (but which may become broken off).................................. 73 Alpigenobombus

4 (3) Midleg basitarsus with the distal posterior corner extended to form a sharp angle of 45° or less, often produced as a narrow tooth or spine (it may be less pronounced in some of the smallest individuals), or if borderline then the cheek (oculo-malar area) in the centre with many small widely-spaced punctures (e.g. B. (Sb.) sibiricus )................................ 5

- Midleg basitarsus with the distal posterior corner broadly or narrowly rounded, but forming an angle of more than 45° and without a narrow tooth or spine, or if borderline then the area between the lateral ocellus and the inner margin of the eye with the unpunctured shining part occupying three quarters of the distance between the lateral ocellus and the eye (e.g. B. (Pr.) hypnorum )............................................................................................. 8

5 (4) Hindleg basitarsus with the proximal posteriorly-directed process with the dense plume of moderately long branched hairs on its proximal surface not continuing onto its outer surface, which is shining and often bare, or at most the outer surface with widely scattered rather reclining short hairs with broad shining areas between them; cheek (oculo-malar area) in the centre smooth and shining at most with a few very shallow punctures; median ocellus with its anterior margin lying on the narrowest line between compound eyes............................................................................ 6

- Hindleg basitarsus with the proximal posteriorly-directed process with the dense plume of moderately long branched hairs on its proximal surface continuing onto its outer surface as a dense erect brush of moderately long branched hairs that obscures the outer surface of the basitarsus between them; cheek (oculo-malar area) in the centre with many small widely-spaced punctures; median ocellus with its anterior margin lying anterior to the narrowest line between the compound eyes.................................................................................................. 81 Sibiricobombus

6 (5) Clypeus central area bulbous and often with at least a very few scattered large or medium punctures, or if the clypeus is mostly smooth and shining then the clypeus has a dorsal median longitudinal groove marked with punctures and the cheek (oculomalar area) is more than half as long as the eye; the corbicular fringes are always longer than the greatest breadth of the hindleg tibia; S6 either without a raised median longitudinal ridge in the posterior one third or if a strong ridge is present then either the clypeus has medium and large punctures or antennal segment A4 is shorter than broad.............................. 7

- Clypeus central area flattened and often smooth and shining with only widely spaced micro-punctures, the larger punctures only at the edges, or if the clypeus is more extensively and densely covered with many small and medium punctures then the corbicular fringes are shorter than the greatest breadth of the hindleg tibia; clypeus without a dorsal median longitudinal groove marked with punctures; cheek less than half as long as the eye; S6 with a raised and often shiny median longitudinal keel in the posterior one third.......................................................... 11 Subterraneobombus

7 (6) S2 usually slightly bulging between the anterior and posterior margins in a weakly rounded transverse ridge; hindleg tibia with the corbicular surface moderately convex and often swollen anteriorly and lacking any posterior concavity in the distal half; clypeus dorsally uniformly convex and always without a deep dorsal median longitudinal groove with many punctures........................................................................................... 27 Thoracobombus

- S2 flat between the anterior and posterior margins, with the weakly bulging transverse ridge absent; hindleg tibia with the corbicular surface nearly flat and only very weakly convex anteriorly and distinctly very slightly concave posteriorly in the distal half; clypeus in its dorsal third usually with a deep median longitudinal groove marked with many punctures.................................................................................................... 16 Megabombus

8 (4) Mandible near its distal posterior corner with a notch (incisura) that is nearly as deep as wide separating a strong posterior tooth (which may become worn down); clypeus in its central area always strongly swollen and bulging, contrasting with deep lateral depressions adjacent and parallel to the labral margin, large punctures dense throughout with few smaller punctures; hindleg basitarsus posterior margin broadly and evenly strongly curved............................. 65 Bombus s. str.

- Mandible near its distal posterior corner with a notch (incisura) that is usually less than half as deep as wide, or often completely lacking and not separating a weak posterior tooth; clypeus in its central area usually weakly swollen or nearly flat, with only shallow lateral depressions adjacent and parallel to the ventral labral margin, large punctures at most widely scattered among many more of the smaller punctures; hindleg basitarsus posterior margin often curved either evenly but weakly, or much more strongly in its proximal half and nearly straight in its distal half....................................... 9

9 (8) Central area of the clypeus with widely scattered large and small punctures, appearing irregular and dull; area between the lat-

eral ocellus and the inner margin of the eye with the band of punctures along the inner margin of the eye dorsally usually for most of its length with very few small punctures, mostly consisting of a few scattered large punctures separated by shining areas broader than the puncture widths, the large unpunctured and shining area adjacent to the ocellus usually large, occupying as much as three quarters of the distance between the lateral ocellus and the inner margin of the eye; hindleg basitarsus in the distal half with short slightly feathered hairs widely spaced so that the shining surface is clearly visible in between................................................................................................. 57 Pyrobombus - Central area of the clypeus with scattered mostly small punctures, appearing smooth and shiney, or if with large punctures then the labrum with the median longitudinal furrow only 0.2× the labral breadth; area between the lateral ocellus and the inner margin of the eye with the band of punctures along the inner margin of the eye dorsally usually with many small and large punctures intermixed and separated by less than the widths of the large punctures, or if there are few small punctures then the part of the puncture band with only large punctures is absent or occupies only a short part of its length and the unpunctured and the shining area adjacent to the ocellus occupies less than half of the distance between the lateral ocellus and the inner margin of the eye; hindleg basitarsus in the distal half with dense overlapping short slightly feathered hairs largely obscuring the shining surface............................................................................76 Melanobombus

10 (2) Mendacibombus : hair of the thoracic dorsum with black and white hairs intermixed without a distinct anterior white band, T4- 5 orange with white tips (Gansu)................................................................. B. waltoni

- Hair of the thoracic dorsum with black and white hairs but with a distinct anterior white band, T4–5 mainly white without orange (Gansu)............................................................................. B. convexus

11(6) Subterraneobombus: clypeus smooth and shining with only micropunctures in its central half, hair of T4–5 either white or yellow or black, or pale with continuous anterior black bands.................................................... 12

- Clypeus rough with small and large punctures scattered throughout, hair of T4–5 yellow with black posteriorly-directed anterior triangles in the middle................................................................... B. amurensis

12(11) Clypeus with the micropunctures sparse, most separated by more than 2× their own breadths; hair of T1–2 either extensively black, or if T1–2 entirely yellow or white, then either T3–4 entirely black, or T3–4 mostly yellow.................... 13

- Clypeus with many micropunctures, many separated by only 2× their own breadths; hair of T1–2 entirely yellow or cream-yellow, T3–4 usually black with broad posterior fringes of long white hairs, or if with only a few pale hairs, then the black band between the wing bases is nearly as broad as the yellow thoracic bands combined and black hairs intermixed throughout the posterior half of the anterior yellow thoracic band (Gansu)......................................... B. personatus

13(12) Hair of T1–2 entirely yellow or white, T3–5 usually entirely black............................................. 14

- Hair of T1–2 either extensively black, or if T1–2 entirely yellow then T3–4 also mostly yellow...................... 15

14(13) Clypeus with a few sparse small punctures in its central half; hair of the thoracic dorsum either entirely yellow, or if a black band is present between the wing bases, then it is less than 0.8× the breadth of the anterior yellow thoracic band; pale hair of the thorax lemon yellow or straw yellow, but usually only cream yellow if faded by the sun; hair (short) on T2 straight and erect over the anterior one quarter (or less), curved and more decumbent over the posterior three quarters; T5 with longest hairs projecting beyond the posterior edge by less than the greatest breadth of the hindleg basitarsus............. B. melanurus

- Clypeus almost devoid of even micropunctures in its central half; hair of the thoracic dorsum with a black band between the wing bases, which is 0.75–1.0× the breadth of the anterior yellow or white thoracic band; pale hair of the thorax cream yellow or white; hair (long) of T2 straight and erect over the anterior two thirds, curved and more decumbent along the posterior edge; T5 with longest hairs projecting beyond the posterior edge by more than the greatest breadth of the hindleg basitarsus (Gansu)........................................................................................ B. difficillimus

15 (13) Hair of T1–3 mostly yellow or brown, T4–5 with yellow or brown or black hair, but never white hair (Neimenggu)............................................................................................... B. distinguendus

- Hair of T1–3 with extensive and conspicuous areas of black, usually with narrow posterior fringes of short white or yellow hairs, T3–5 with conspicuous white hair (Neimenggu)........................................... B. subterraneus

16 (7) Megabombus : cheek (oculo-malar area) length <1.5× the breadth of the mandible at its base between and including the mandibular articulations; hair of T3 black with a yellow patch near the midline, tail orange................... B. bicoloratus

- Cheek (oculo-malar area) length>1.5× the breadth of the mandible at its base between and including the mandibular articulations; hair of T3 and tail black or brown or yellow or white or orange........................................... 17

17 (16) Hair of the thoracic dorsum yellow or orange or brown, without an obvious band of black hairs between the wing bases... 18

- Hair of the thoracic dorsum yellow or orange or brown, with an obvious band of black hairs between the wing bases..... 21

18 (17) Antennal segment A4 shorter than broad.................................................................. 19

- Antennal segment A4 as long as or longer than broad........................................................ 20

19 (18) Hair of T3-6 black at most with a few slightly paler hairs in posterior fringes and especially at the sides, thoracic dorsum orange-brown, corbicular fringes black but sometimes with pale tips.................................... B. longipes

- Hair of T3–6 black with broad posterior white fringes, thoracic dorsum yellow, corbicular fringes pale...... B. ussurensis

20 (18) Hair of the thoracic dorsum yellow or yellow-brown, lower side of the thorax nearly white, T4–5 extensively white, corbicular fringes extensively pale tipped, hair long....................................................... B. consobrinus

- Hair of the thoracic dorsum orange-brown, lower side of the thorax black, T4–5 extensively orange or yellow, corbicular fringes black, hair short...................................................................... B. koreanus

21 (17) Hair of the thoracic dorsum white with a broad black band between the wing bases, at least T3 bright red (Gansu)................................................................................................... B. supremus

- Hair of the thoracic dorsum entirely black or with some yellow or brown hairs anteriorly and posteriorly, T3 black or brown or yellow or white...................................................................................... 22

22 (21) Antennal segment 4 shorter than broad, hair of T5 orange.......................................... B. trifasciatus

- Antennal segment 4 as long as or longer than broad, hair of T5 black or brown or yellow or white.................... 23

23(22) Hair of the thoracic dorsum usually bright yellow with a clearly defined black band between the wing bases, the yellow with- out black hairs extensively intermixed.................................................................... 25

- Hair of the thoracic dorsum predominantly black with only dull yellow or brown hairs intermixed anteriorly and posteriorly in very weakly defined bands............................................................................. 24

24(23) Hair of the side of the thorax and T1 black or orange................................................ B. koreanus

- Hair of the side of the thorax and T1 pale yellow-white........................................... B. consobrinus

25(23) Hair of T1 bright lemon yellow, T2 entirely black, T5 more than the median half stretching from the midline is black................................................................................................. B. religiosus

- Hair of T1 dull sand yellow, T2 yellow at least anteriorly, T5 predominantly white at most with the median third black.... 26

26 (25) Short hair of the face pale, thoracic dorsum with the black band between the wing bases without yellow hairs intermixed, lower side of the thorax and the leg bases entirely white, T2–3 sometimes predominantly pale, hair length medium.... B. sushkini

- Short hair of the face black, thoracic dorsum with the black band between the wing bases often with yellow hairs intermixed, lower side of the thorax and the leg bases predominantly black or at least with many black hairs intermixed, T2–3 predomi- nantly black, hair very short..................................................................... B. czerskii

27(7) Thoracobombus: hair of the thoracic dorsum orange-brown, any black hairs on the thoracic dorsum either concentrated anteri- orly or in a minority and not obviously forming a distinct black band or spot between the wing bases.................. 28

- Hair of the thoracic dorsum grey or yellow or brown, with a distinct black band or spot or obviously greater concentration between the wing bases............................................................................... 35

28(27) Corbicular fringes predominantly black or sometimes a few hairs with pale tips, hair of the face predominantly black or some- times the short hair is yellow........................................................................... 29

- Corbicular fringes predominantly yellow or sometimes a few hairs black, hair of the face predominantly yellow......... 32

29(28) Hair of T3–6 entirely black................................................................... B. opulentus

- Hair of T3–6 extensively orange or yellow................................................................ 30

30 (29) Hair of the side of the thorax black, thoracic dorsum and T1–5 entirely bright orange-red, wings uniformly dark brown (Shaanxi)................................................................................... B. atripes

- Hair of the side of the thorax may be black but usually brown or yellow or white, thoracic dorsum and T1–5 extensively yel- low, or if orange then the side of the thorax with orange hairs at least intermixed and T5 often with some black hairs, wings yellow near the body and grey distally.................................................................... 31

31(30) Hair of the face mostly black or grey, T1–4 when viewed from the side nearly uniformly orange, T 4 in the median area with the hairs rising from flat punctures separated by 1–2× their own breadths................................ B. hedini (part)

- Shorter hair of the face and T1 yellow, T2–4 when viewed from the side orange anteriorly and yellow posteriorly, T 4 in the median area with the hairs rising from raised pustulate punctures separated by 0.5–1× their own breadths...... B. tricornis

32(28) Hair of T2–3 with some black laterally................................................................... 33

- Hair of T2–3 without black laterally..................................................................... 34

33(32) Hair of T5 often with very little black but T2–4 with small patches of black laterally or rarely medially on some segments, tho- racic dorsum grey or brown with many black hairs concentrated anteriorly (Neimenggu)............. B. pascuorum (part)

- Hair of T2 usually with very little black but T3–5 with broad black anterior bands, thoracic dorsum orange with few scattered black hairs................................................................................ B. schrencki

34(32) T3–5 with the median posterior hairless areas large and smooth and very shiny, corbicular surface in the proximal third strongly convex and forming a strong longitudinal ridge.......................................... B. laesus (part)

- T3–5 with the median posterior hairless areas small and striate and dull, corbicular surface in the proximal third weakly convex without a strong longitudinal ridge (Neimenggu)................................................. B. muscorum

35(27) Hair of the tail bright orange........................................................................... 36

- Hair or the tail yellow or grey or black................................................................... 37

36(35) Hair of T2 yellow with black intermixed laterally, T3 predominantly black, thoracic dorsum with either a more (queens) or a less (workers) well defined band of black between the wing bases....................................... B. remotus

- Hair of T2 grey or yellow anteriorly with orange posteriorly, sometimes with black extensively between them, T3 predomi- nantly orange, thoracic dorsum with a well defined band of black between the wing bases, the black extending posteriorly in a median point.............................................................................. B. impetuosus

37(35) Hair of the thoracic dorsum yellow or white with a very well defined band or spot of black between the wing bases with few or no black hairs intermixed in the anterior pale band, T4–5 yellow or white with few or no black hairs.................. 38

- Hair of the thoracic dorsum brown or yellow or white with black intermixed between the wing bases and with many black hairs intermixed in the anterior pale band, T4–5 brown or yellow or white with many black hairs......................... 41

38(37) Hair of T2–3 extensively black (Neimenggu)........................................................... B. exil

- Hair of T2–3 yellow.................................................................................. 39

39(38) Hair of the face and the femora of the legs almost entirely bright lemon yellow (Neimenggu).............. B. anachoreta

- Hair of the face and the femora of the legs with many black hairs.............................................. 40

40 (39) Hair of the corbicular fringes and S2–5 black..................................................... B. filchnerae

- Hair of the corbicular fringes and S2–5 with yellow intermixed..................................... B. laesus (part)

41(37) Hair of the thoracic dorsum with some brown at least posteriorly.............................................. 42

- Hair of the thoracic dorsum grey and black................................................................ 43

42(41) Hair of the thoracic dorsum brown sometimes with black intermixed, side of the thorax black with some brown intermixed, hair short................................................................................ B. hedini (part)

- Hair of the thoracic dorsum brown posteriorly and grey anteriorly with black widely intermixed, side of the thorax grey with- out black intermixed, hair long (Neimenggu)............................................... B. pascuorum (part)

43(41) Hair of T3–4 with few black hairs, pale hair of the thoracic dorsum posteriorly distinctly more grey than the yellow of T3–4............................................................................................. B. humilis

- Hair of T3–4 with narrow bands of black hairs anteriorly, pale hair of the thoracic dorsum posteriorly a similar grey-yellow to the pale hairs of T3–4................................................................................. 44

44(43) Hair of T2 laterally with patches of black, midleg tibia posterior fringe usually with many long pale hairs.. B. deuteronymus

- Hair of T2 laterally with few or no black hairs, midleg tibia posterior fringe mostly black with a few pale tips (Neimenggu)...................................................................................... B. pseudobaicalensis

45(1) Psithyrus : T6 very strongly curved under the metasoma so that the apex points anteriorly, S6 strongly projecting distally (at the tip) beyond T6 as a shiny curved spine, the lateral keels small as just short curved bumps........................... 46

- T6 at most weakly curved under the metasoma so that the apex points ventrally, S6 scarcely projecting distally (at the tip) beyond T6, the lateral keels long and strongly projecting..................................................... 48

46(45) Hair of the thoracic dorsum with broad yellow bands anteriorly and posteriorly, T1 predominantly yellow...... B. skorikovi

- Hair of the thoracic dorsum with a broad yellow band anteriorly but posteriorly black or with only a few pale hairs, T1 predom- inantly black........................................................................................ 47

47 (46) T6 medially with a weak shiny longitudinal ridge for most of its length, T1 usually without pale hairs........ B. norvegicus

- T6 dorsally flat without a median longitudinal ridge, T1 with some pale hairs............................ B. sylvestris

48(45) Tail white or yellow.................................................................................. 49

- Tail red or orange or pinkish........................................................................... 53

49(48) Hair of the thorax predominantly yellow, sometimes with a few black hairs scattered between the wing bases or a small black spot, hair very short (Shaanxi)................................................................... B. bellardii

- Hair of the thoracic dorsum yellow with a black band between the wing bases, hair length medium................... 50

50(49) Hair of T1–2 yellow, labrum with a large median sharp acute triangular projection before the ventral margin (Gansu).................................................................................................. B. expolitus

- Hair of T1–2 predominantly black, labrum with a broad median rounded obtuse triangular projection before the ventral margin................................................................................................... 51

51(50) T6 strongly shining with only very shallow micropunctures, hair of the thoracic dorsum with only an anterior yellow band, the posterior black, the tail white.................................................................. B. bohemicus

- T6 with many medium-sized punctures, hair of the thoracic dorsum with anterior and posterior yellow bands, the tail yellow................................................................................................... 52

52(51) T6 matte with close punctures and a median longitudinal ridge, S6 with the lateral keels curving round to meet each other in a semi-circle with scarcely a trace of extensions towards the posterior apex.............................. B. barbutellus

- T6 shining with broadly scattered punctures and no median longitudinal ridge, S6 with the lateral keels S-shaped, curving round to meet each other but then curving back towards the posterior apex.............................. B. campestris

53(48) Hair of the body mostly black without yellow or white bands......................................... B. coreanus

- Hair of the body with some yellow or white bands.......................................................... 54

54 (53) Hair of T1–3 extensively black with small yellow posterior fringes laterally on T2–3....................... B. rupestris

- Hair of T1 entirely yellow or white, T2 with yellow or white at least anteriorly, T3 entirely black or with a narrow orange pos- terior fringe across its breadth.......................................................................... 55

55(54) Hair of T2 entirely yellow, S6 with the lateral keels only very weakly angled midway along their length, narrow, and scarcely visible projecting beyond T6 from the dorsal aspect (Gansu).......................................... B. tibetanus

- Hair of T2 extensively black at least laterally, S6 with the lateral keels strongly angled midway along their length, broad, and clearly visible projecting beyond T6 from the dorsal aspect................................................... 56

56(55) Labrum with a median sharp and acute triangular projection before the ventral margin..................... B. cornutus

- Labrum with a median broadly rounded projection before the ventral margin............................. B. chinensis

57(9) Pyrobombus : hair of the thoracic dorsum posteriorly entirely black............................................. 58

- Hair of the thoracic dorsum posteriorly entirely pale or with pale hair intermixed.................................. 59

58 (57) Hair of the thoracic dorsum entirely black, legs predominantly orange................................. B. flavescens

- Hair of the thoracic dorsum anteriorly with a broad yellow band, legs predominantly black.................. B. infirmus

59(57) Hair of the thoracic dorsum entirely orange-brown, without black hair even between the wing bases.......... B. hypnorum

- Hair of the thoracic dorsum yellow or white, with either black hair intermixed at least in part or often with a black band between the wing bases............................................................................... 60

60(59) Pale hair of the thoracic dorsum white, the black hair always forming a distinct band between the wing bases........... 61

- Pale hair of the thoracic dorsum yellow, the black hair either forming a band between the wings or intermixed more broadly.................................................................................................... 62

61(60) Hair of the head predominantly grey, corbicular fringes orange.......................................... B. lepidus

- Hair of the head predominantly black, corbicular fringes black although often with pale tips............... B. lemniscatus

62(60) Hair of the upper quarter of the side of the thorax and T2 pale with many black hairs intermixed (Gansu)...... B. infrequens

- Hair of the side of the thorax and T2 pale without black hairs intermixed........................................ 63

63(62) Hair of T5 either black but with a posterior white fringe or entirely white, thoracic dorsum either predominantly pale yellow with a few scattered black hairs between the wings or with a weakly defined black band.................... B. modestus

- Hair of T5 orange although sometimes very pale, thoracic dorsum always with many black hairs either scattered evenly throughout or concentrated between the wings as a weakly defined black band.................................... 64

64(63) Corbicular fringes orange or yellow but rarely in some queens black, hair of the thoracic dorsum usually with yellow and black hairs evenly intermixed, only in some queens with a distinct black band between the wing bases, the anterior and posterior yellow bands equal in breadth measured along the midline, T3 yellow or orange with black hairs intermixed anteriorly, only in some queens predominantly black................................................................. B. picipes

- Corbicular fringes with many hairs part black (at least the short ones), hair of the thoracic dorsum with a black band between the wing bases, the anterior yellow band much broader than the posterior band measured along the midline, T3 black with a narrow posterior pale fringe..................................................................... B. wangae

65 (8) Bombus s. str.: hair of T4–5 red or orange................................................................. 66

- Hair of T4–5 nearly white............................................................................. 67

66 (65) Hair of the face black, thoracic dorsum anteriorly and T2 black or black with a few golden yellow hairs laterally, T4–5 deep red, hindleg tibia with the corbicular fringes black.................................................... B. ignitus

- Hair of the face black with bright orange hairs below antenna, thoracic dorsum anteriorly with grey hairs intermixed, T2 dull yellow, T4–5 pale orange, hindleg tibia with the corbicular fringes with at least the tips orange......... B. patagiatus (part)

67(65) Cheek (oculo-malar area) distinctly shorter than broad; hair of the face and the lower side of the thorax black or yellow or white; wings clear or lightly clouded with brown........................................................... 68

- Cheek (oculo-malar area) nearly as long as broad; hair of the face and the lower side of the thorax black; wings lightly clouded with brown (Neimenggu)..................................................................... B. sporadicus

68 (67) Hair of the thoracic dorsum with the pale anterior band bright lemon yellow, the posterior band (scutellum) usually with few or no pale hairs, side of the thorax with the lower half black or with many black hairs intermixed....................... 69

- Hair of the thoracic dorsum with the pale anterior band very pale yellow or cream or white, the posterior pale band (scutellum) broad and of the same colour, side of the thorax with the lower half pale or with many black hairs intermixed........... 71

69 (68) Upperside (vertex) of the head, side of the thorax, thoracic dorsum posteriorly (scutellum) and T1 laterally with unusually abundant long thickly feathery hair intermixed, queens usually with much feathery hair of the face light grey..................................................................................................... B. longipennis

- Upperside (vertex) of the head, side of the thorax, thoracic dorsum posteriorly (scutellum) and T1 laterally without unusually abundant long thickly feathery hair intermixed, queens with the short feathery hair of the face black.................. 70

70 (69) Labral lamella narrow (in queens, often lamella breadth <0.4× labral breadth), T2 with punctures in the medial posterior area dense with strong intervening surface sculpturing.................................................. B. cryptarum

- Labral lamella broad (in queens, often lamella breadth> 0.4× labral breadth), T2 with punctures in the medial posterior area sparse with weak intervening surface sculpturing (Neimenggu)........................................ B. lucorum

71 (68) Hair of the thoracic dorsum with the pale anterior and posterior bands very pale yellow or cream, lower side of the thorax with some pale and black hairs intermixed....................................................... B. lantschouensis

- Hair of the thoracic dorsum with the pale anterior and posterior bands white, lower side of the thorax usually with white hair but sometimes with many black hairs intermixed........................................................... 72

72 (71) Hair of the thoracic dorsum with the black band between the wing bases clearly defined, with very few white hairs intermixed within it laterally, and with few black hairs intermixed at the front of the anterior pale band or in the pale posterior (scutellar) band, side of the thorax in its lower half white or with many black hairs intermixed (Neimenggu)....... B. patagiatus (part)

- Hair of the thoracic dorsum with the black band between the wing bases weakly defined, white hairs intermixed throughout but especially densely laterally, and with many black hairs intermixed at the front of the anterior pale band or in the pale posterior (scutellar) band, side of the thorax in its lower half white (Gansu).................................. B. minshanensis

73 (3) Alpigenobombus: hair of the thoracic dorsum with a black band between the wing bases between broad anterior and posterior pale bands.......................................................................................... 75

- Hair of the thoracic dorsum predominantly black or with olive-grey hair, any pale bands narrow and heavily intermixed with black.............................................................................................. 74

74(73) Hair of the thoracic dorsum dark olive-grey with paler hairs along the midline............................ B. grahami

- Hair of the thoracic dorsum predominantly black, anteriorly often with a few grey hairs intermixed (Gansu)...... B. validus

75 (73) Hair of the thoracic dorsum pale bands white, hair long, wings clear (Gansu).......................... B. kashmirensis

- Hair of the thoracic dorsum pale bands golden yellow, hair short, wings dark brown....................... B. breviceps

76 (9) Melanobombus: hair of the thoracic dorsum white or brown, between the wings without a black band.......... B. festivus

- Hair of the thoracic dorsum white or yellow, between the wings either with a broad black band or the thoracic dorsum almost entirely black....................................................................................... 77

77 (76) Hair of the thoracic dorsum predominantly black, T3–5 red........................................... B. pyrosoma

- Hair of the thoracic dorsum with broad white or yellow bands, either T3 mostly black or T5 white.................... 78

78 (77) Hair of the thoracic dorsum with the pale bands white....................................................... 79

- Hair of the thoracic dorsum with the pale bands yellow (Gansu)....................................... B. keriensis

79 (78) Hair of the face black, T3 with some red, T5 white.......................................................... 80

- Hair of the face usually white, T3 black with white at the sides, T5 pale orange or pale pink but not white........ B. sichelii

80 (79) Hair of the lower half of the side of the thorax black, T2 either entirely black or anteriorly with some bright yellow, body size medium and hair of medium length (Gansu).................................................... B. rufofasciatus

- Hair of the lower half of the side of the thorax usually white, T2 anteriorly white or cream or rarely yellow, body size small and hair long (Gansu).......................................................................... B. ladakhensis

81 (5) Sibiricobombus: hair of the thoracic dorsum yellow without black but often with an orange band between the wing bases, T3 yellow..................................................................................... B. sibiricus

- Hair of the thoracic dorsum yellow and always with a black band between the wing bases, T3 black (Gansu).... B. asiaticus