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 : 16-20

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

1 Gonostylus with the inner proximal process without medium-length branched hairs; volsella and gonostylus usually strongly sclerotised and mid or dark brown in colour; volsella often but not always with a process or hooks on its inner margin; penisvalve head either straight, or curved inwards, or curved outwards............................................... 2

- Gonostylus with the inner proximal process associated with many medium-length branched hairs; volsella and gonostylus usually weakly sclerotised and pale yellowish in colour; volsella always without a process or hooks on its inner margin; penisvalve head always nearly straight................................................................42 Psithyrus

2 (1) Antenna medium to long, reaching back at least to the anterior margin of the tegula at the wing base; penis spatha narrowly and sharply pointed at its proximal end; penis-valve head either straight, or curved inwards, or curved outwards; eye either enlarged or not enlarged relative to any females............................................................. 3

- Antenna short, not quite reaching back to the anterior margin of the tegula at the wing base; penis spatha rounded at its proximal end; penis-valve head always straight; eye always strongly enlarged relative to any females........10 Mendacibombus

3 (2) Penis valve narrow dorso-ventrally, at least in its distal third, which is slightly ventrally curved; antenna either of medium length or longer, reaching to or beyond the tegula at the wing base.............................................. 4

- Penis valve greatly broadened dorso-ventrally so as to form half of a broad tube, the distal end flared outwards as half of a broad ‘funnel’; antenna of medium length, not reaching back as far as the posterior margin of the tegula at the wing base........................................................................................... 63 Bombus s. str.

4 (3) Penis-valve head from the dorsal aspect turned inwards distally as a distinct broad hook, either dorso-ventrally flattened in the form of a ‘sickle’ or as an incurved ‘spoon’................................................................ 6

- Penis-valve head from the dorsal aspect distally either nearly straight or turned slightly outwards, at most with only a tiny inwardly curved narrow point........................................................................... 5

5 (4) Volsella in ventral aspect in its distal half broad, the inner hooks placed either close to the midpoint of its length between its broadest point and the distal end, or if close to the distal end then reduced to a broad blunt process; gonostylus with the inner proximal process often weakly sclerotised in the ventral part of the shelf, and if it has a long spine then this is usually nearly straight sharp and inwardly pointed; hind tibia with the outer surface inside the posterior margin convex...................................................................................................... 26 Thoracobombus

- Volsella in ventral aspect in its distal half narrow, the inner hooks pointed and always placed close to the distal end; gonostylus with the inner proximal process uniformly strongly sclerotised and strongly re-curved away from the body midline and back towards the distal part of the gonostylus, with either at least one long strongly curved tubular spine with a blunt tip or flatter and with many teeth; hind tibia with the outer surface inside the posterior margin concave, or if convex then the volsella has the more anterior of the inner hooks with many radiating teeth.................................... 16 Megabombus

6 (4) Gonostylus usually a simple triangle, always without an inner proximal process; gonostylus with the inner distal margin at least slightly thickened in cross section with a submarginal longitudinal groove........................ 55 Pyrobombus

- Gonostylus very variable in shape, but usually with a distinct inner proximal process; gonostylus with the inner distal margin simple flattened and blade-like in cross section without a submarginal longitudinal groove........................... 7

7 (6) Penis-valve shaft with a ventral angle about half way along its length and distinct either as a pronounced sharp angle or produced as a larger transverse process....................................................................... 8

- Penis-valve shaft with a ventral angle about half way along its length either reduced and very broadly rounded (not sharply marked) or absent..................................................................................... 9

8 (7) Penis-valve head turned inwards distally as an incurved ‘bowl’ or ‘spoon’ shape; penis-valve shaft with the ventral angle about half way along its length produced ventrally and laterally as a broad transverse paddle-like process; mandible distally pointed and with one anterior tooth............................................................ 11 Subterraneobombus

- Penis-valve head turned inwards distally as a dorso-ventrally flattened ‘sickle’ shape; penis-valve shaft with the ventral angle about half way along its length produced ventrally as a pronounced angle; mandible distally pointed and with two anterior teeth............................................................................... 71 Alpigenobombus

9 (7) Mid basitarsus on its outer surface with many medium and long hairs; gonostylus with the distal lobe at least just shorter than broad; antenna either medium or long, reaching to or beyond the tegula at the wing base...............74 Melanobombus

- Mid basitarsus on its outer surface with sparse short hairs and very few or no moderate and long hairs; gonostylus with the distal lobe always longer than broad; antenna very long, reaching distinctly beyond the wing base........ 79 Sibiricobombus

10(2) Mendacibombus : hair of the thoracic dorsum with black and white hairs intermixed without a distinct anterior white band, T4–6 black or orange with white tips (Gansu)....................................................... B. waltoni

- Hair of the thoracic dorsum with black and white hairs and with a distinct anterior white band, T4–6 mainly white and without orange (Gansu)............................................................................. B. convexus

11(8) Subterraneobombus: gonocoxa with a sharp dorsal ridge reaching all the way to the distal edge, on its inner side distally with a dorsally flat or concave triangular inwardly directed process................................................. 14

- Gonocoxa with the sharp dorsal ridge subsiding into the convex dorsal surface before the distal edge, so that the distal portion is rounded and finger like, or if the sharp dorsal ridge subsides only just before the distal edge then the gonostylus lacks a distinct and narrowed inner proximal process................................................................ 12

12(11) Hair of T3–7 yellow with small triangles of black anteriorly and medially; gonostylus approximately or nearly as long as broad with the apex truncate with two weakly marked angles, the inner proximal process at its narrowest point almost as broad as the length of the gonostylus; penis-valve head proximal outer corner with a long proximally-directed process; penis-valve ventrolateral process often with teeth but without long spine.............................................. B. amurensis

- Hair of T3–7 black; gonostylus much shorter than broad and triangular with the apex with one angle, the inner proximal pro-

cess at its narrowest point half as broad as the length of the gonostylus; penis-valve head proximal outer corner without a long proximally-directed process; penis-valve ventro-lateral process with a dorsal and a ventral long spine................. 13 13(12) Hair of the face yellow, or if black then there is no band of black hairs between the wing bases; gonostylus with the inner proximal process breadth at its narrowest 0.25× the length of the gonostylus; hair short and even............... B. melanurus

- Hair of the face usually black, but if with many pale hairs then there are few or no pale hairs just above the wing base in the black band between the wing bases; gonostylus with the inner proximal process at its narrowest as broad as nearly 0.5× the length of the gonostylus; hair long and uneven (Gansu)........................................... B. difficillimus

14(11) Either hair of T2 black anteriorly or hair of T4 entirely yellow or white; penis-valve head on its outer proximal corner with a toothed ridge, with two distinct anteriorly-directed flattened teeth or processes.................................... 15

- Hair of T1–2 yellow, T3–6 anteriorly black and posteriorly yellow or white; penis-valve head on its outer proximal corner with a simple anteriorly-directed long conical or cylindrical spine (Gansu)................................. B. personatus

15(14) Penis valve with the ventro-lateral process with a strong dorsal tooth; the majority of the hairs just dorsal to the antennal base and anterior to the ocelli black; T2 with black hairs usually intermixed for at least 0.5× the length from the anterior to posterior edges so as to appear as at least a conspicuous brown band, but occasionally reduced to inconspicuous patches of a few black hairs intermixed laterally near the anterior edge (Neimenggu)...................................... B. subterraneus

- Penis valve with the ventro-lateral process with a weak dorsal tooth; the majority of at least the shorter hairs just dorsal to the antennal base usually yellow; T2 without any black hair (Neimenggu).............................. B. distinguendus

16 (5) Megabombus : cheek (oculo-malar area) length <1.5× the breadth of the mandible at its base between and including the mandibular articulations; volsella with the posterior (distal) inner process about as long as broad; hair of T3 black with a yellow patch near the midline, tail orange, body size very large............................................ B. bicoloratus

- Cheek (oculo-malar area) length>1.5× the breadth of the mandible at its base between and including the mandibular articulations; volsella with the posterior (distal) inner process much longer than broad; hair of T3 and tail black or brown or yellow or white or orange, body size medium...................................................................... 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 or spot of black hairs between the wing bases.................................................................................................... 21

18 (17) Antennal segment 4 as long as or shorter than broad; gonostylus with a single inner proximal process forming a long narrow curved spine; volsella with the posterior (distal) inner process divided into two with the anterior branch broad like a hammer head.............................................................................................. 19

- Antennal segment 4 longer than broad; gonostylus with the inner process forming a broad flat plate; volsella with the posterior (distal) inner process divided into two with the anterior branch reduced to a small tooth............................ 20

19 (18) Hair of the thoracic dorsum orange-brown, T5–7 black with a few paler hairs in posterior fringes and especially at the sides.............................................................................................. B. longipes

- Hair of the thoracic dorsum yellow, T5–7 black with broad posterior white fringes........................ B. ussurensis

20 (18) Hair of the thoracic dorsum dull yellow or yellow-brown, upper half of the side of the thorax nearly white and paler than the thoracic dorsum, face usually with many long hairs pale as well as some black, hair long................ B. consobrinus

- Hair of the thoracic dorsum yellow-brown or orange-brown, upper half of the side of the thorax dull yellow-brown or orangebrown and similar in colour to the thoracic dorsum, face usually with the long hairs mostly black, hair short.... B. koreanus

21(17) Hair of the thoracic dorsum white with a 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 as long as or shorter than broad; gonocoxa distally broad, beyond it the gonostylus forming a short broad rectangular strap; hair of T5 orange........................................................... B. trifasciatus

- Antennal segment 4 longer than broad; gonocoxa distally narrowed to a rounded point, beyond it the gonostylus triangular; 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 or small spot between the wing bases, the yellow without black hairs extensively intermixed.......................................................... 24

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

24 (23) Volsella with the distal inner process divided into two hooks with the anterior branch forming a broad cone separated from the posterior branch and about half as long as the posterior branch, gonostylus with the inner basal process reduced to a long conical posteriorly directed spine; hair of T5 black over at least the median half with pale lateral tufts............ B. religiosus

- Volsella with the distal inner process divided into two hooks with the anterior branch forming a short tooth on the side of the posterior branch and much less than half as long as the posterior branch, gonostylus with the inner basal process flattened and broad; hair of T5 pale at most only narrowly interrupted medially with black..................................... 25

25 (24) Hair of the face with many black hairs intermixed, thoracic dorsum yellow with a clearly defined black band between the wing bases...................................................................................... B. sushkini

- Hair of the face with few black hairs intermixed, thoracic dorsum predominantly yellow with a poorly defined small black spot between the wing bases........................................................................ B. czerskii

26(5) Thoracobombus: hair of the thoracic dorsum orange-brown, any black hairs on the thoracic dorsum in a minority and not obvious and not forming a distinct black band or spot between the wing bases........................................ 27

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

27 (26) Hair of T4–5 entirely black................................................................... B. opulentus

- Hair of T4–5 with some orange or yellow or grey........................................................... 28

28 (27) Gonostylus with the proximal inner process reduced to two long curved spines, the distal posterior part of the gonostylus longer than broad....................................................................................... 29

- Gonostylus with the proximal inner process forming a flattened plate sometimes with a one long spine, the distal posterior part of the gonostylus shorter than broad..................................................................... 30

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

- Hair of the thoracic dorsum yellow-brown, T1–5 with varying proportions of yellow and black, wings nearly clear................................................................................................... B. tricornis

30 (28) Volsella projecting beyond the gonostylus posteriorly as a broad rectangle that is just longer than broad with two distal corners that are scarcely pointed, the double-hooked inner projection clearly separate more anteriorly.................. B. laesus

- Volsella projecting beyond the gonostylus posteriorly as a single long curved narrow triangle or spine, the double-hooked inner projection clearly separate more anteriorly................................................................ 31

31 (30) Hair of the thoracic dorsum lemon yellow intermixed with many black hairs, sometimes slightly fewer black hairs anteriorly and posteriorly, T2 predominantly lemon yellow sometimes with a few black hairs intermixed posteriorly, T5–6 often with orange..................................................................................... B. remotus

- Hair of the thoracic dorsum orange-brown either with few black hairs or with the black hairs much more numerous in the anterior three quarters.................................................................................... 32

32 (31) Gonostylus enlarged with the proximal inner projection with a strong elbow so that the main part of its length is directed posteriorly as a long straight narrow spine of almost uniform diameter; hair of the thoracic dorsum often with many black hairs intermixed, especially in the anterior three quarters (Neimenggu).................................... B. pascuorum

- Gonostylus unenlarged with the proximal inner projection either directed in towards the midline, or if directed more posteriorly then it is triangular and gradually narrowing towards the tip; hair of the thoracic dorsum usually with few black hairs. 33

33 (32) Volsella posteriorly in lateral view broadly rounded at the apex; hair of the thoracic dorsum anteriorly and posteriorly narrowly yellow, T1-6 yellow without black hair (Neimenggu).............................................. B. muscorum

- Volsella posteriorly in lateral view narrowly pointed at the apex; hair of the thoracic dorsum brown without yellow but sometimes with some black, T1–6 brown or yellow often with black anteriorly........................................ 34

34 (33) Hair of T2–6 anteriorly black and posteriorly grey, hair long.......................................... B. schrencki

- Hair of T2–6 predominantly orange or with black hair anteriorly on T4–6, hair short......................... B. hedini

35 (26) Antenna with segments A11–12 expanded to give a clubbed end, strongly concave on the posterior side (Neimenggu). B. exil

- Antenna with segments A11–12 similar in diameter to A9–10 and nearly cylindrical............................... 36

36(35) Hair of T3–6 orange........................................................................ B. impetuosus

- Hair or T3–6 with some yellow or grey or black............................................................ 37

37 (36) Hair of the thoracic dorsum anterior and posterior bands yellow............................................... 38

- Hair of the thoracic dorsum anterior and posterior bands grey-white............................................ 40

38 (37) Volsella projecting beyond the gonostylus posteriorly as a broad rectangle that is just longer than broad with two distal corners that are scarcely pointed, the double-hooked inner projection clearly separate more anteriorly.................. B. laesus

- Volsella projecting beyond the gonostylus posteriorly as a single rounded or pointed triangle, the double-hooked inner projection reduced to a long blunt stump but clearly separate more anteriorly.......................................... 39

39 (38) Volsella projecting beyond the gonostylus posteriorly as a rounded triangle; hair of legs and T7 predominantly black................................................................................................. B. filchnerae

- Volsella projecting beyond the gonostylus posteriorly as a pointed triangle; hair of legs and T7 predominantly yellow (Neimenggu).............................................................................. B. anachoreta

40 (37) Hair of T3–4 with few black hairs, pale hair of the thoracic dorsum posteriorly distinctly more grey than the yellow of T3–4; volsella with the long inner process ending in a deeply divided Y shaped double hook....................... B. humilis

- Hair of T3–4 with narrow bands of black hairs anteriorly, pale hair of the thoracic dorsum posteriorly a similar grey to the pale hairs of T3–4; volsella with the long inner process ending in a broad blunt stump or a long narrow spoon shape......... 41

41 (40) Volsella with the long inner process ending in a long narrow spoon shape; midleg tibia posterior fringe predominantly grey......................................................................................... B. deuteronymus

- Volsella with the long inner process ending in a broad blunt stump; midleg tibia posterior fringe predominantly black (Neimenggu)......................................................................... B. pseudobaicalensis

42 (1) Psithyrus : volsella in its posterior distal half beyond the inner corner greatly narrowed, almost parallel sided, and finger shaped, gonostylus with only a few long hairs.............................................................. 43

- Volsella distally either broader in the form of a broad nearly triangular plate, or if the distal part is narrowed then the inner corner is very strongly produced, gonostylus usually with many long hairs around the inner proximal.................... 45

43 (42) Hair of the thoracic dorsum with the pale anterior and posterior bands of nearly equal breadth measured along the body midline........................................................................................... B. skorikovi

- Hair of the thoracic dorsum black with a narrow band of yellow anteriorly and a few pale hairs scattered posteriorly...... 44

44 (43) Antennal scape with weak surface sculpturing and shiny............................................. B. sylvestris

- Antennal scape with strong surface sculpturing and matte........................................... B. norvegicus

45 (42) Penis valve half way along its length with the ventral lateral angle reduced to a small notch and not visible from the dorsal aspect............................................................................................. 46

- Penis valve half way along its length with the ventral lateral angle strongly and broadly produced ventrally and outwardly so that it is visible from the dorsal aspect.................................................................... 47

46 (45) Hair of the thoracic dorsum and T1 entirely black, T4–7 orange....................................... B. coreanus

- Hair of the thoracic dorsum with yellow anterior and posterior bands with black between the wing bases, T1 yellow or black, T4–7 white or black........................................................................ B. bohemicus

47 (45) Hair of T5 orange or red............................................................................... 52

- Hair of T5 black or yellow or white...................................................................... 48

48 (47) Pale hair of T5 black or black with white tips.............................................................. 49

- Pale hair of T5 entirely white or yellow................................................................... 50

49 (48) Hair of the thoracic dorsum posteriorly black, S2–4 black; gonostylus and volsella weakly sclerotised (pale), penis valve with the ventral lateral angle distally narrowed so that it is almost a spine (Gansu)............................ B. tibetanus

- Hair of the thoracic dorsum posteriorly with yellow or pale tips, S2–4 with pale tips; gonostylus and volsella strongly sclerotised (dark), penis valve with the ventral lateral angle distally broadened so that it is almost a right angle distally (Gansu)............................................................................................. B. expolitus

50 (48) Hair of the thoracic dorsum usually predominantly yellow with only a small black spot between the wing bases, T4–5 predominantly yellow, hair very short, wings dark brown (Shaanxi)........................................... B. bellardii

- Hair of the thoracic dorsum with yellow bands anteriorly and posteriorly and a black band between the wing bases, T4–5 predominantly yellow or white, hair long, wings nearly clear.................................................... 51

51 (50) Volsella distally rounded, gonostylus about as long as broad; hair of the side of the thorax predominantly black, T4–5 white.......................................................................................... B. barbutellus

- Volsella distally pointed, gonostylus much shorter than broad; hair of the side of the thorax yellow, T4–5 yellow..................................................................................................... B. campestris

52 (47) Volsella in its distal posterior half very pale yellow, with the inner corner strongly produced in towards the the mid-line to almost twice the volsella breadth halfway along the distal half................................................. 54

- Volsella in its distal posterior half brownish, with the inner corner scarcely produced in towards the the mid-line......... 53

53 (52) Gonocoxa from the inner aspect distally broadened and tuncate, with a double pointed end, gonostylus broader near the inner side and narrowing towards the outer side......................................................... B. cornutus

- Gonocoxa from the inner aspect distally narrowed to a single pointed end, gonostylus narrower near the inner side and broadening towards the outer side...................................................................... B. turneri

54 (52) Volsella in its distal posterior half beyond the inner corner forming a broad, almost equilateral triangle, with the inner margin only weakly incurved or almost straight when viewed perpendicularly to the dorsal surface; pale hair of the thoracic dorsum yellow or white............................................................................. B. chinensis

- Volsella in its distal posterior half beyond the inner corner distinctly longer than broad, with the inner margin strongly incurved when viewed perpendicularly to the dorsal surface; pale hair of the thoracic dorsum yellow................. B. rupestris

55 (6) Pyrobombus : exoskeleton of the midleg and hindleg tibiae and tarsi orange-brown, fringed with orange-yellow hairs, the hindleg tibia outer surface often almost covered in midlength orange hairs.............................. B. flavescens

- Exoskeleton of the midleg and hindleg tibiae and tarsi nearly black, fringed with black or yellow hairs, the hindleg tibia outer surface with the central area hairless and shiny............................................................. 56

56 (55) Hair of the thoracic dorsum with a very obvious band of black between the wing bases, the edges sometimes indistinct because of intermixing of black and pale hairs.................................................................... 57

- Hair of the thoracic dorsum with no obvious band of black between the wing bases, although there may be some black hairs intermixed.......................................................................................... 59

57 (56) Hair of the thoracic dorsum anteriorly and T1 predominantly white................................... B. lemniscatus

- Hair of the thoracic dorsum anteriorly and T1 predominantly yellow............................................ 58

58 (57) Hair of T4–6 orange............................................................................ B. lepidus

- Hair of T4–6 black sometimes with white tips..................................................... B. infirmus

59 (56) Hair of the thoracic dorsum orange-brown, T3 black............................................... B. hypnorum

- Hair of the thoracic dorsum predominantly yellow, T3 with at least a broad pale posterior fringe...................... 60

60 (59) Penis-valve shaft in lateral view much (1.4x) broader beyond the ventral angle about half way along its length; hair of the thoracic dorsum anteriorly yellow with many scattered black hairs intermixed....................................... 61

- Penis-valve shaft in lateral view scarcely (1.1x) broader beyond the ventral angle about half way along its length; hair of the thoracic dorsum anteriorly yellow without any black hairs.................................................... 62

61 (60) Hair of T3–5 short and entirely bright yellow........................................................ B. picipes

- Hair of T3–5 long with about equal amounts of black and yellow intermixed (Gansu)..................... B. infrequens

62(60) Hair of the thoracic dorsum without black hairs between the wing bases, T5–6 without pale orange hairs....... B. modestus

- Hair of the thoracic dorsum with a band between the wing bases with black hairs intermixed, T5–6 often with some pale orange hairs................................................................................. B. wangae

63 (3) Bombus s. str.: hair of the thoracic dorsum pale bands and T1–2 golden yellow, T5–6 orange-red; penis-valve head in dorsal view straight, with the tip not turned outwards from the body midline..................................... B. ignitus

- Hair of the thoracic dorsum pale bands and T1–2 lemon yellow, white, or brownish-yellow, T5–6 white, yellow, pink, or brown, sometimes with some black; penis-valve head in dorsal view with the tip turned outwards from the body midline.. 64

64 (63) Hair of the face always black, thoracic dorsum pale bands and T1–2 brownish yellow; wings light brown; penis-valve head in dorsal view where it is turned outwards on its inner distal margin uniformly convex (Neimenggu).......... B. sporadicus

- Hair of the face often pale, thoracic dorsum pale bands and T1–2 lemon yellow or white; wings nearly clear or slightly grey; penis-valve head in dorsal view where it is turned outwards on its inner distal margin concave....................... 65

65 (64) Gena posterior to the eye and on the scutellum with obvious dense long thickly branched feathery hairs; hair of the thoracic dorsum posteriorly usually black, rarely the branched hairs grey and the long hairs of the posterior fringe yellow..........

........................................................................................ B. longipennis - Gena posterior to the eye and on the scutellum with only weakly branched hairs, a little more branched on the scutellum; hair of the thoracic dorsum posteriorly black or yellow or white................................................... 66

66 (65) Hair of the face black or if yellow then with many black hairs intermixed, the thoracic dorsum posteriorly with the yellow band narrow and black hairs on the body generally rarely with pale tips, T3 almost entirely black and usually without a complete posterior pale fringe, T4 predominantly white, T5 bright white...................................... B. cryptarum

- Hair of the face and the thoracic dorsum posteriorly broadly yellow or white or if this pale band is weak then the black hairs on the body generally often have pale tips, T3 black but often posteriorly with a strong pale fringe, T4 predominantly black or yel- low or brown or pink, T5 white or yellow or brown or pink................................................... 67

67 (66) Hair of T5 orange-pink.................................................................. B. patagiatus (part)

- Hair of T5 white, yellow, or rarely brown mixed with black................................................... 68

68 (67) Hair of the thoracic dorsum anterior pale band without scattered black hairs in the anterior half...................... 69

- Hair of the thoracic dorsum anterior pale band with a few scattered black hairs in the anterior half.................... 70

69 (68) Hair of the thoracic dorsum posterior band broadly yellow, similar in breadth to the anterior yellow band, T5 yellow, cream, or rarely brown mixed with black, black hairs on the body generally without pale tips................... B. lantschouensis

- Hair of the thoracic dorsum posterior band narrowly yellow, less than half of the breadth of the anterior yellow band, T5 bright white, black hairs on the body often with pale tips (Neimenggu)....................................... B. lucorum

70 (68)Hair of the thoracic dorsum pale bands and T1 white or cream-white (Neimenggu)................... B. patagiatus (part)

- Hair of the thoracic dorsum pale bands and T1 yellow (Gansu).................................... B. minshanensis

71(8) Alpigenobombus: hair of the thoracic dorsum with a black band between the wing bases between broad anterior and posterior pale bands.......................................................................................... 73

- Hair of the thoracic dorsum predominantly black or with olive-grey hair, any pale bands narrow and heavily intermixed with black.............................................................................................. 72

72 (71) 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

73 (71) 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

74 (9) Melanobombus: hair of the thoracic dorsum uniformly orange brown.................................... B. festivus

- Hair of the thoracic dorsum yellow or white, usually with a band of black between the wing bases.................... 75

75 (74) Eyes distinctly enlarged relative to those of any female bumblebees; hair of T1 white, T2 yellow, T5–6 predominantly white (Gansu)................................................................................. B. rufofasciatus

- Eyes similar in relative size to those of any female bumblebees; hair of T1–2 both yellow or both white, T5–6 predominantly orange or orange with white tips........................................................................ 76

76 (75) Penis-valve recurved head broadly fused to the adjacent penis-valve shaft so that it is spear-shaped; hair of T5–6 orange with white tips (Gansu)......................................................................... B. ladakhensis

- Penis-valve recurved head not fused to the adjacent penis-valve shaft so that it is sickle-shaped; hair of T5–6 orange without white tips.......................................................................................... 77

77 (76) Gonostylus <0.5× as long as broad, the volsella projecting beyond the gonostylus by>2× the length of the gonostylus; hair of T3 orange.................................................................................. B. pyrosoma

- Gonostylus nearly 1× as long as broad, the volsella projecting beyond the gonostylus by <1× the length of the gonostylus; hair of T3 black......................................................................................... 78

78 (77) Volsella with the distal inner process having a marked inner basal corner so that the process forms a broad short stump; hair of T2 along the posterior margin black, T4 anteriorly black especially broadly laterally......................... B. sichelii

- Volsella with the distal inner process having an obscure broadly rounded inner basal corner so that the process forms a narrow curved hook; hair of T2 entirely yellow, T4 entirely orange (Gansu).................................... B. keriensis

79 (9) Sibiricobombus: hair of the thoracic dorsum yellow without black but often with a broad 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