1	♀♀: antenna with 10 flagellomeres; outer side of foretarsomere I with markedly long spines (Fig. 1A)	2
–	♂♂: antenna with 11 flagellomeres; spines on outer side of foretarsomere I as long as other spines, not markedly long (Fig. 1B)	44
♀♀
2(1)	Metanotum without tubercles (indistinct median impression may be present in some specimens) (Fig. 1C)	3
–	Metanotum with markedly developed median pair of tubercles (Fig. 1D, E)	34
3(2)	Claw teeth perpendicular to inner margin of claw (Fig. 2A)	4
–	Claw teeth obliquely oriented to inner margin of claw (Fig. 2B)	15
Sphex resplendens group
4(3)	Legs black or dark brown; scape black or dark brown	5
–	Legs at least partly orange or bright ferruginous; scape for most part orange	14
5(4)	Cellular wing area largely hyaline (Fig. 2C–E)	6
–	Cellular wing area fuscous (Fig. 2F)	10
6(5)	Metasoma entirely black or dark blue; length of petiole approximately equal to flagellomere II	7
–	Apical three metasomal terga and apical three to four metasomal sterna orange; petiole slightly shorter than flagellomere II	Sphex mimulus R. Turner
7(6)	Propodeal enclosure finely sculptured, without transverse ridges (Fig. 3A); clypeal surface plain	8
–	Propodeal enclosure markedly ridged (Fig. 3B–C); clypeal surface ventrally with curved wrinkles (Fig. 4E, 19B)	Sphex imporcatus sp. n.
8(7)	Appressed pubescence and erect setae on clypeus silvery-white (Fig. 6A–C)	Sphex gracilis sp. n.
–	Apressed pubescence silvery-white, but erect setae on clypeus dark brown or black (Fig. 6E)	9
9(8)	Wing veins orange to light brown (Fig. 2D); pubescence on propodeal enclosure black (Fig. 5E); wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D)	Sphex gilberti R. Turner
–	Wing veins brown (Fig. 2C, E, F); pubescence on propodeal enclosure silvery-white (Fig. 5A–C); wing membrane without yellow tinge (Fig. 2C, E)	Sphex luctuosus F. Smith
10(5)	Metasoma entirely black or dark blue	11
–	Metasoma at least partly ferruginous	13
11(10)	Pubescence on propodeal enclosure silvery-white (Fig. 5A–C)	12
–	Pubescence on propodeal enclosure black (Fig. 5E)	Sphex resplendens Kohl
12(11)	Petiole longer than flagellomere II; free clypeal margin without lobes (Fig. 6A)	Sphex rugifer Kohl
–	Length of petiole approximately equal to flagellomere II; free clypeal margin with pair of lobes (Fig. 6D–E)	Sphex fumipennis F. Smith
13(10)	Petiole shorter than flagellomere II; wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D); free clypeal margin with pair of lobes (Fig. 6E)	Sphex mimulus R. Turner
–	Petiole longer than flagellomere II; wing membrane without yellow tinge (Fig. 2C, E, F); free clypeal margin without lobes (Fig. 6A)	Sphex rugifer Kohl
14(4)	Mesosoma orange	Sphex rhodosoma (R. Turner)
–	Mesosoma black	Sphex darwiniensis R. Turner
Sphex subtruncatus group
15(3)	Legs black or dark brown	16
–	Legs at least partly orange or bright ferruginous	32
16(15)	Appressed pubescence and erect setae on clypeus silvery-white or golden (Fig. 6A–D)	17
–	Apressed pubescence silvery-white, but erect setae on clypeus dark brown or black, at least some of them and at least at tips (Fig. 6E)	28
17(16)	Wing veins brown to black (Fig. 2C, E, F)	18
–	Wing veins at least partially bright orange (Fig. 2D)	24
18(17)	Scutellum flat (Fig. 3E)	19
–	Scutellum convex medially (Fig. 3D, F)	20
19(18)	Petiole longer than flagellomere II; pubescence on propodeal enclosure not concealing sculpture (Fig. 5C)	Sphex jucundus sp. n.
–	Petiole shorter than flagellomere II; pubescence on propodeal enclosure completely concealing sculpture (Fig. 5A, B, D)	Sphex ermineus Kohl
20(18)	Pubescence on propodeal enclosure silvery-white (Fig. 5A–C)	21
–	Pubescence on propodeal enclosure golden (Fig. 5D)	23
21(20)	Wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D)	Sphex cognatus F. Smith
–	Wing membrane without yellow tinge (Fig. 2C, E, F)	22
22(21)	Scutellum without impression (Fig. 3D–E); clypeus without glabrous stripe (Fig. 2G), with golden appressed pubescence (Fig. 6D); free clypeal margin with pair of lobes (Fig. 6D–E)	Sphex argentatissimus sp. n.
–	Scutellum with median impression (Fig. 3F); clypeus with medial glabrous stripe (Fig. 2H), with appressed silvery-white pubescence (Fig. 6A–C, E); free clypeal margin without lobes (Fig. 6A)	Sphex bilobatus Kohl
23(20)	Wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D); clypeus without glabrous stripe (Fig. 2G)	Sphex cognatus F. Smith
–	Wing membrane without yellow tinge (Fig. 2C); ventral part of clypeus glabrous (Fig. 6A)	Sphex vestitus F. Smith
24(17)	Petiole longer than flagellomere II	25
–	Petiole shorter than flagellomere II	Sphex brevipetiolus sp. n.
25(24)	Scutellum without impression (Fig. 3D–E)	26
–	Scutellum with median impression (Fig. 3F)	27
26(25)	Pubescence on propodeal enclosure completely concealing sculpture (Fig. 5A, B, D)	Sphex cognatus F. Smith
–	Pubescence on propodeal enclosure not concealing sculpture (Fig. 5C, E)	Sphex formosellus van der Vecht
27(25)	Pubescence on propodeal enclosure completely concealing sculpture (Fig. 5A, B, D)	Sphex cognatus F. Smith
–	Pubescence on propodeal enclosure not concealing sculpture (Fig. 5C)	Sphex pretiosus sp. n.
28(16)	Cellular wing area largely hyaline (Fig. 2C–E)	29
–	Cellular wing area fuscous (Fig. 2F)	Sphex ahasverus Kohl
29(28)	Scutellum flat (Fig. 3E); petiole shorter than flagellomere II	30
–	Scutellum convex medially (Fig. 3D, F); petiole longer than flagellomere II	31
30(29)	Pubescence on propodeal enclosure completely concealing sculpture (Fig. 5A, B, D)	Sphex ermineus Kohl
–	Pubescence on propodeal enclosure not concealing sculpture (Fig. 5C)	Sphex corporosus sp. n.
31(29)	Wing membrane with yellow tinge in cellular wing area (Fig. 2D)	Sphex modestus F. Smith
–	Wing membrane without yellow tinge (Fig. 2C, E, F)	Sphex finschii Kohl
32(15)	Metasoma entirely black; scape black or dark brown	Sphex basilicus (R. Turner)
–	Metasoma at least partly ferruginous; scape for most part orange	33
33(32)	Clypeus with silvery-white appressed pubescence (Fig. 6A–C, E)	Sphex flammeus sp. n.
–	Clypeus with golden appressed pubescence (Fig. 6D)	Sphex staudingeri Gribodo
Sphex argentatus group
34(2)	Legs black or dark brown; metasoma entirely black or dark blue; scape black or dark brown	35
–	Legs at least partly orange or bright ferruginous; metasoma at least partly ferruginous; scape for most part orange	42
35(34)	Appressed pubescence and erect setae on clypeus silvery-white or golden (Fig. 6A–D)	36
–	Appressed pubescence silvery-white, but erect setae on clypeus dark brown or black, at least some of them and at least at tips (Fig. 6E)	39
36(35)	Wing veins brown to black (Fig. 2C, E, F)	37
–	Wing veins at least partially bright orange (Fig. 2D)	38
37(36)	Clypeus without glabrous stripe (Fig. 2G)	Sphex argentatus Fabricius
–	Clypeus with medial glabrous stripe (Fig. 2H)	Sphex carbonicolor van der Vecht
38(36)	Petiole longer than flagellomere II	Sphex pretiosus sp. n. (member of Sphex subtruncatus group)
–	Petiole shorter than flagellomere II	Sphex brevipetiolus sp. n. (member of Sphex subtruncatus group)
39(35)	Scutellum flat (Fig. 3E); petiole shorter than flagellomere II	Sphex corporosus sp. n.
–	Scutellum convex medially (Fig. 3D, F); petiole longer than flagellomere II	40
40(39)	Wing membrane with yellow tinge in cellular wing area (Fig. 2D)	Sphex modestus F. Smith
–	Wing membrane without yellow tinge (Fig. 2C, E, F)	41
41(40)	Clypeus with silvery-white appressed pubescence (Fig. 6A–C, E); pubescence on propodeal completely concealing sculpture (Fig. 5C)	Sphex finschii Kohl
–	Clypeus with golden appressed pubescence (Fig. 6D); pubescence on propodeal enclosure not concealing sculpture (Fig. 5B)	Sphex ephippium F. Smith
42(34)	Propodeal enclosure finely sculptured, without transverse ridges (Fig. 3A)	43
–	Propodeal enclosure markedly transversely ridged (Fig. 3C)	Sphex sericeus (Fabricius)
43(42)	Wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D), metasoma partly black	Sphex decoratus F. Smith
–	Wing membrane without yellow tinge (Fig. 2C, E, F), metasoma entirely ferruginous	Sphex flammeus sp. n. (member of Sphex subtruncatus group)
♂♂
44(1)	Metanotum without tubercles (indistinct median impression may be present in some specimens) (Fig. 3)	45
–	Metanotum with markedly developed median pair of tubercles (Fig. 4/5)	70
45(44)	Claw teeth perpendicular to inner margin of claw (Fig. 1)	46
–	Claw teeth obliquely oriented to inner margin of claw (Fig. 2)	51
Sphex resplendens group
46(45)	Metasoma entirely black or dark blue	47
–	Three apical metasomal terga pale yellowish-orange	Sphex mimulus R. Turner
47(46)	Cellular wing area largely hyaline (Fig. 2C–E)	48
–	Cellular wing area fuscous (Fig. 2F)	49
48(47)	Appressed pubescence and erect setae on clypeus silvery-white (Fig. 6A)	Sphex gracilis sp. n.
–	Appressed pubescence silvery-white, but erect setae on clypeus dark brown or black, at least some of them and at least at tips (Fig. 6E)	Sphex luctuosus F. Smith
49(47)	Propodeal enclosure and clypeus with silvery-white pubescence (Fig. 5A–C and Fig. 6A–C)	50
–	Pubescence on propodeal enclosure black (Fig. 5E); clypeus with appressed golden pubescence (Fig. 6D)	Sphex resplendens Kohl
50(49)	Forewing apically and hindwing distally brighter, remainder of the wing area markedly fuscous (Fig. 16A, B)	Sphex fumipennis F. Smith
–	Wings fuscous except for hindwing, which is hyaline basally (Fig. 24B, C)	Sphex rugifer Kohl
Sphex subtruncatus group
51(45)	Legs black or dark brown	52
–	Legs at least partly orange or bright ferruginous	66
52(51)	Apical part of metasomal sternum VIII divided into two large lobes (Fig. 4A)	53
–	Apical part of metasomal sternum VIII entire (Fig. 4B–D)	65
53(52)	Apex of metasomal sternum VIII broadly or narrowly pointed (Fig. 4B, C)	54
–	Apex of metasomal sternum VIII notched (Fig. 4D, 39B)	59
54(53)	Appressed pubescence and erect setae on clypeus silvery-white or golden (Fig. 6A–D); lateral margin of metasomal sternum VIII shallowly concave (Fig. 4C)	55
–	Appressed pubescence silvery-white, but erect setae on clypeus dark brown or black, at least some of them and at least at tips (Fig. 6E); lateral margin of metasomal sternum VIII straight or slightly convex (Fig. 4B, D)	58
55(54)	Clypeus with golden pubescence (Fig. 6D), without glabrous stripe (Fig. 2G)	56
–	Clypeus with silvery-white pubescence (Fig. 6A–C), with medial glabrous stripe (Fig. 6C)	57
56(55)	Free clypeal margin without lobes (Fig. 6A); pubescence on propodeal enclosure not concealing sculpture (Fig. 5C)	Sphex formosellus van der Vecht
–	Free clypeal margin with pair of lobes (Fig. 6D); pubescence on propodeal enclosure completely concealing sculpture (Fig. 5A, B, D)	Sphex cognatus F. Smith
57(55)	Wings light brown, markedly fuscous along subcosta and below submedial cell (Fig. 36)	Sphex fortunatus sp. n.
–	Wings entirely hyaline (Fig. 2C)	Sphex jucundus sp. n.
58(54)	Wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D)	Sphex modestus F. Smith
–	Wing membrane without yellow tinge (Fig. 2C, E, F)	Sphex finschii Kohl
59(53)	Wing veins brown to black (Fig. 2C, E, F)	60
–	Wing veins at least partially bright orange (Fig. 2D)	64
60(59)	Lateral margin of metasomal sternum VIII straight or slightly convex (Fig. 4B, D)	61
–	Lateral margin of metasomal sternum VIII shallowly concave (Fig. 4C)	62
61(60)	Pubescence on propodeal enclosure silvery-white (Fig. 5A); clypeus without glabrous stripe (Fig. 2G); free clypeal margin plain, without lobe (Fig. 6A)	Sphex argentatissimus sp. n.
–	Pubescence on propodeal enclosure golden (Fig. 5D); ventral part of clypeus glabrous (Fig. 6A); free clypeal margin broadly emarginated, with a broad triangular median lobe (Fig. 6B)	Sphex vestitus F. Smith
62(60)	Petiole longer than flagellomere II	Sphex argentatissimus sp. n.
–	Petiole shorter than flagellomere II	63
63(62)	Clypeus with appressed silvery-white pubescence (Fig. 6A–C, E); pubescence on propodeal enclosure not concealing sculpture (Fig. 5C)	Sphex corporosus sp. n.
–	Clypeus with appressed golden pubescence (Fig. 6D); pubescence on propodeal enclosure completely concealing sculpture (Fig. 5A, B)	Sphex ermineus Kohl
64(59)	Petiole longer than flagellomere II; pubescence on propodeal enclosure golden (Fig. 5D); wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D)	Sphex pretiosus sp. n.
–	Petiole shorter than flagellomere II; pubescence on propodeal enclosure silvery-white (Fig. 5A–C); wing membrane without yellow tinge (Fig. 2C)	Sphex corporosus sp. n.
65(52)	Free clypeal margin entirely black (Fig. 2G)	Sphex bilobatus Kohl
–	Free clypeal margin at least partially bright orange (Fig. 2H)	Sphex latilobus sp. n.
66(51)	Apical part of metasomal sternum VIII entire (Fig. 4B–D)	67
–	Apical part of metasomal sternum VIII divided into two large lobes (Fig. 4A)	69
67(66)	Metasoma entirely black; erect setae on clypeus dark brown or black, at least some of them and at least at tips (Fig. 6E)	Sphex caelebs sp. n.
–	Metasoma at least partly ferruginous; erect setae on clypeus silvery-white or golden (Fig. 6A–D)	68
68(67)	Wing veins brown (Fig. 2C, E, F); scape for most part orange; pubescence on propodeal enclosure and appressed pubescence on clypeus golden (Fig. 5D and Fig. 6D)	Sphex staudingeri Gribodo
–	Wing veins at least partially bright orange (Fig. 2D); scape black or dark brown; pubescence on propodeal enclosure and appressed pubescence on clypeus silvery-white (Fig. 5A–C and Fig. 6A–C, E)	Sphex semifossulatus van der Vecht
69(66)	Pubesence on propodeal enclosure silvery-white (Fig. 5A–C); free clypeal margin at least partially bright orange and without lobes (Fig. 2H)	Sphex latilobus sp. n.
–	Pubescence on propodeal enclosure golden (Fig. 5D); free clypeal margin entirely black and with single median lobe (Fig. 6B)	Sphex basilicus (R. Turner)
Sphex argentatus group
70(44)	Appressed pubescence and erect setae on clypeus silvery-white (Fig. 6A–C)	71
–	Appressed pubescence silvery-white, but erect setae on clypeus dark brown or black, at least some of them and at least at tips (Fig. 6E)	74
71(70)	Apex of metasomal sternum VIII broadly or narrowly pointed (Fig. 4B, C)	72
–	Apex of metasomal sternum VIII notched (Fig. 4D, 39B)	73
72(71)	Propodeal enclosure finely sculptured, without transverse ridges (Fig. 3A); clypeus without glabrous stripe (Fig. 2G); free clypeal margin concave towards center, with short median lobe (Fig. 6B)	Sphex argentatus Fabricius
–	Propodeal enclosure markedly transversely ridged (Fig. 3C); clypeus with medial glabrous stripe (Fig. 2H); free clypeal margin concave towards center, but without median lobe (Fig. 6A)	Sphex sericeus (Fabricius)
73(71)	Lateral margin of metasomal sternum VIII straight or slightly convex (Fig. 4D); petiole slightly longer than flagellomere II	Sphex carbonicolor van der Vecht
–	Lateral margin of metasomal sternum VIII shallowly concave (Fig. 4C); petiole shorter than flagellomere II	Sphex corporosus sp. n.
74(70)	Wing membrane at least partially with yellow tinge in cellular wing area (Fig. 2D)	Sphex modestus F. Smith
–	Wing membrane without yellow tinge (Fig. 2C, E, F)	75
75(74)	Clypeus with appressed silvery-white pubescence (Fig. 6A–C, E); pubescence on propodeal enclosure not concealing sculpture (Fig. 5C)	Sphex finschii Kohl
–	Clypeus with appressed golden pubescence (Fig. 6D); pubescence on propodeal enclosure completely concealing sculpture (Fig. 5B)	Sphex ephippium F. Smith