Some fairly major changes have been made. The Promus section (37 to 41) has had some adjustments to aid with more diverse forms of its species, and E. nigrina (continuation) and E. inornata have been moved from around couplet 44, to couplets 81 and 82, this should help with distinguishing from E. humeralis, which has also been altered. I have also made a few small miscellaneous changes. More info in my profile: https://www.inaturalist.org/people/6449260
The key on Google Drive (looks nicer and can be saved): https://drive.google.com/file/d/1eFmmPiPeA57nQSG4Lhp-saTloFgfcFMI/view?usp=drivesdk
1 Mesofemora and metafemora dentate or subdentate...2
1’ Mesofemora and metafemora never dentate...4
2 Pronotum widest anterior of middle, elytra with simple punctures, widespread...E. armata
2’ Pronotum widest at middle, elytral punctures simple or muricate, Baja California...3
3 Elytra usually appearing rough, metatibia more or less straight...E. moesta
3’ Elytra appearing smooth, metatibia curved or bent...E. femorata
4 Size small, pronotum generally cordate and constricted at base, elytral apex not attenuate or caudate, roughly sculptured, never sulcate, sometimes with short setae, usually distributed across beaches, forests, and mountains, rarely in arid regions...subgenus Blapylis
4’ Size variable, pronotum usually not cordate, if so then punctures smaller and more minute, pronotum often slightly constricted at base, elytral apex variable, roughly sculptured, sulcate, setose or not, widespread across all environments...5
5 Legs long with an unproportionately small body, robust or not, body often flattened if not robust, never sulcate, if legs shorter, then body elongate or robust and flattened, size smaller...6
5’ Legs long or short but with body fairly proportionate, only rarely flattened, sulcate or not, if legs fairly long, then not with conspicuous setae, or a small, elongate, and flattened body, size variable...22
6 Body generally slender or rarely robust, always flattened, pronotal and elytral sculpturing simple (except in E. nigrina), elytra usually more parallel sided, never with conspicuous setae...7
6’ Body, generally robust, never flattened, pronotal and elytral sculpturing complex, elytra usually more ventricose, usually with conspicuous setae...18
7 Elytral sculpturing muricate or scabrous, southern New Mexico to Canada, Sierra Nevada Mountains to Rocky Mountains...E. nigrina (in part)
7’ Elytral sculpturing simple, always below the northernmost edge of Colorado’s border...8
8 Range only in the Inyo White Mountains...9
8’ Range widespread but not in the Inyo White Mountains...10
9 Profemora with blunt tooth, anterolateral angles of pronotum blunt, but projected, legs shorter...E. aalbui
9’ Profemora only sinuate, anterolateral angles of pronotum slightly projected, legs longer...E. microps
10 Range near western Texas and the Guadalupe Mountains...11
10’ Range in the Southwest United States excluding Texas and the Guadalupe Mountains...13
11 Apex of the the probasitarsus with a brush of golden setae, range in the Guadalupe Mountains...E. guadalupensis
11’ Probasitarsus lacking golden setae, only with orange spines, range near southwestern Texas...12
12 Mentum with finger-like process at the center of its frontal margin, pronotum lacking projected anterolateral angles, widest at middle, near Rio Grande river...E. labialis
12’ Mentum without finger-like process, pronotum with projected anterolateral angles, Big Bend National Park...E. easterlai
13 Range in the Mohave and Colorado Deserts of California, pronotum usually evenly arcuate, strial punctures larger than those of intervals...E. californica
13’ Range in Arizona, Utah, and the Colorado Desert, pronotum rarely evenly arcuate, strial punctures variable, but if in the Colorado Desert, then punctures of striae and intervals small and subequal in size...14
14 Anterolateral angles of pronotum strongly projected, caves near the Arizona-Utah border...E. wynnei
14’ Anterolateral angles of pronotum not projected or only slightly projected, if strongly projected then not near the Arizona-Utah border...15
15 Strial punctures medium sized, larger than those of intervals…16
15’ Strial punctures smaller, subequal to those of intervals…17
16 Anterolateral angles of pronotum projected, Sky Islands in southeast Arizona...E. dissimilis
16’ Anterolateral angles not projected, truncate, the Grand Canyon...E. leptoscelis
17 Size smaller, Sonoran Desert including the Colorado Desert...E. delicata (E. nevadensis)
17’ Size larger, northern Arizona and southern Utah, usually in forested areas...E. wheeleri
18 Fairly large tubercles present on elytra...19
18’ Elytra without large tubercules, or tubercules quite small...20
19 Range in southern California to Oregon...E. granosa
19’ Range near the Four Corners...E. leechi
20 Pronotum evenly tuberculate, Oregon...E. spoliata
20’ Pronotum punctate, widespread...21
21 Antennas robust, body generally more robust, setae shorter...E. hirsuta
21’ Antennas thin, body generally more slender, setae longer...E. pilosa
22 Size small or sometimes medium, covered in long setae, restricted to coastal and sometimes inland California, or rarely in western Nevada, or the Sonoran Desert...23
22’ Size small or large, usually glabrous, if with conspicuous setae then not found in coastal California, nor in Baja California, or the Sonoran Desert, and if found in western Nevada then third antennomere not shortened...28
23 Males with dentate profemora and elytra caudate, Sonoran Desert...E. tribulus
23’ Males nor females ever caudate or attenuate, non-arid California and/or western Nevada...24
24 Third antennomere shortened, body smaller and more slender, pill shaped, setae yellow, coastal California and towards and into western Nevada...E. littoralis
24’ Third antennomere not shorted, body larger, California...25
25 Size 13mm or more...26
25’ Size 12mm or less...27
26 Setae usually orange, pronotum constricted at base, California and Baja California...E. osculans
26’ Setae black or grey, pronotum not constricted at base, Baja California...E. ursus
27 Setae black, pronotum constricted at base, California and Baja California...E. nigropilosa
27’ Setae yellow, pronotum not constricted at base, Baja California...E. subdeplanata
28 Elytra caudate at least in males and very rough, near Tamaulipas if not caudate, size usually fairly large...29
28’ Elytra caudate or not, but if caudate and roughly textured then elytra only slightly rough, elytra can be rough if not caudate and not near Tamaulipas, size large or small...31
29 Only males caudate with profemora dentate, Tamaulipas...E. fiski
29’ Both males and females caudate with mutic profemora, Four Corners and Sierra Nevada region...30
30 Elytra lacking long setae, Four Corners...E. caudifera
30’ Elytra always with long setae, Sierra Nevada region...E. longipilosa
31 Elytral sculpture very rough, elytra always attenuate but never caudate, pronotum wide, California or slightly into Nevada or Oregon...32
31’ Elytral sculpture variable but if rough then elytra never attenuate and pronotum never wide, widespread...33
32 Luster shiny and elytral apex acutely attenuate, Pacific coast...E. marginata
32’ Luster dull and elytral apex blunt but still attenuate, Sierra Nevada Mountains...E. scabricula (E. acutangula)
33 Body small and fusiform, punctures usually small and scattered, sometimes with minute setae, pronotum never sinuate before its base...34
33’ Shape rarely fusiform, if so, then punctures larger and in rows, pronotum sinuate before base, or size large...37
34 Elytra carinate and with minute setae…35
34’ Elytra without carina or minute setae...36
35 Line where pronotum and elytra meet nearly a perfect straight line, coastal Texas and Louisiana...E. veterator
35’ Line where pronotum and elytra meet rounded, making the elytra’s humeral angles appear projected, northern Texas to Canada...E. opaca
36 Body more fusiform, hind angles of pronotum quite a bit wider than anterolateral angles...E. fusiformis
36’ Body less fusiform, hind angles and anterolateral angles about the same width...E. extricata (in part)
37 Size medium, elytra inflated, apex rounded, and legs shorter, or elytra fairly elongate, apex slightly attenuate, and legs longer, elytral striae composed of large, moderately spaced, conspicuous punctures, pronotum fairly parallel sided, luster fairly dull, never caudate, Texas and southeast New Mexico...E. goryi
37’ Elytral striae not composed of large punctures, if so then size smaller and luster shiny...38
38 Size medium, elytra usually flattened, always attenuate, and heavily punctate, although punctures in rows, pronotum arcuate, luster shiny, never sulcate, caudate, or carinate, south and central Texas...E. striolata
38’ Size, elytra, punctures, luster, and pronotum variable, though if in south and central Texas then elytra sulcate, caudate, or carinate, or elytra less heavily punctate, widespread...39
39 Size medium, body subfusiform, often droplet shaped, luster usually dull, pronotum widest at middle, parallel sided or arcuate, elytra usually glabrous although rarely with minute setae, inflated or not, apex often slightly attenuate and with a split between both elytra, profemora dentate in males, never sulcate, caudate, or carinate, Arizona, New Mexico, and Texas…40
39’ Size, luster, pronotum, and elytra variable, body rarely fusiform or subfusiform if not quite elongate and lacking dentate profemora, even more rarely droplet shaped, setose, sulcate, caudate, carinate or not, widespread…42
40 Elytra with minute setae and heavily punctate, eastern Texas…E. spiculifera
40’ Elytra glabrous and punctures inconspicuous, Arizona and New Mexico…41
41 Pronotum more or less parallel sided, anterolateral angles almost always projected outwards, prosternum forming large triangular wedge...E. subnitens
41’ Pronotum evenly arcuate, anterolateral angles only rarely projected outwards, prosternum not forming large triangular wedge...E. madrensis
42 Size almost always larger than 19mm, almost always with legs long, no matter the size, sometimes caudate, profemora often dentate, at least in males...43
42’ Size almost always smaller than 19mm, if larger, then legs almost always short unless body is fusiform, legs are often long if body in normal size range, never caudate, profemora only rarely dentate...70
43 Body elongate, elytra sometimes inflated, pronotum usually not all that distinct from elytra (subfusiform), if the pronotum and elytra are fairly distinct, then elytra smooth, prosternum projected downwards or profemora strongly sinuate, profemora never dentate and never with caudate elytra, punctures simple and minute, never sulcate...44
43’ Body fairly variable, sometimes elongate, often robust, pronotum usually quite distinct from elytra, almost always with dentate profemora, if missing then profemora slightly sinuate, elytra sometimes caudate, sulcate or not...47
44 Elytra with red line running down the length of the elytra, this line never diffuses into black...E. ornatipennis
44’ Elytra entirely black, or if a red line is present along the elytra it diffuses into black...45
45 Profemora strongly sinuate, pronotum widest slightly anterior of middle...E. hepburni
45’ Profemora simple, pronotum widest at middle...46
46 Prosternum smaller, only slightly projecting downwards, restricted to California...E. gigantea
46’ Prosternum larger prominently projecting downwards, widespread but not found in California...E. longicollis
47 Elytra with carina, if carina absent and the elytra either sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum rounded off and the pronotum widest anterior of middle, pronotum concave or convex...48
47’ Elytra lacking carina, if elytra sulcate or with numerous irregular punctures, then anterolateral angles of the pronotum acute, or if angles not acute then pronotum widest at middle, pronotum convex...53
48 Pronotum concave...E. suturalis
48’ Pronotum convex...49
49 Elytra with carina...E. acuta
49’ Elytra without carina...50 (E. obscura)
50 Elytra with clear, prominent striae...51
50’ Elytra without clear, prominent striae...52
51 Elytra deeply sulcate, west of the Great Plains...E. obscura sulcipennis
51’ Elytra slightly sulcate, Great Plains...E. obscura obscura
52 Elytra with simple punctures, western Texas and southern New Mexico...E. obscura glabrisulca
52’ Elytra with muricate punctures, Four Corners...E. obscura dispersa
53 Elytra with large glabrous costae, intervals minutely hirsute and often coated in white debris, caudate or not, legs long...E. mirabilis
53’ Elytra variable but without costae, caudate or not...54
54 Pronotum usually wide and strongly arcuate, humeral angles of elytra obsolete, apex rounded...E. grandicollis
54’ Pronotum variable, if wide, then elytral apex attenuate at least, humeral angles of elytra not obsolete...55
55 Elytra strongly sulcate, at least on elytral apex…56
55’ Elytra not strongly sulcate…57
56 Pronotum widest anterior to middle, anterolateral angles of pronotum acute, widespread…E. hispilabris
56’ Pronotum widest at middle, anterolateral angles of pronotum rounded off, Texas…E. composita
57 Restricted to California and Baja California, if not in California then tibia strongly curved, profemoral spine small and blunt, and in Nevada, northwest Arizona, or extreme southwest Utah...58
57’ Widespread, but not found in California, Baja California, Nevada, northwest Arizona, or southwest Utah...64
58 Pronotum two or more times wider than the head, often caudate...E. acuticauda
58’ Pronotum less then two times wider than the head, rarely caudate...59
59 Pronotum more or less parallel sided, widest at middle, Mohave and Colorado Deserts, Nevada and Arizona...60
59’ Pronotum not parallel sided, or if so then elytral apex strongly attenuate and with groove in between both elytra, if in the Mohave or Colorado Desert then pronotum widest anterior of middle…61
60 Tibia strongly curved, profemoral spines blunt, never caudate...E. subcylindrica
60’ Tibia not strongly curved, profemoral spines acute, males caudate...E. mexicana
61 Pronotum widest at middle...62
61’ Pronotum widest anterior of middle...63
62 Elytra glabrous, punctures simple, luster shiny, elytral apex with groove in between the elytra, Baja California…E. discincta
62’ Elytra setose, punctures muricate, luster dull, elytral apex without groove in between the elytra, Channel Islands…E. adumbrata
63 Pronotum usually broad and strongly arcuate, widespread across California but absent near the U.S.-Mexico border…E. dentipes
63’ Pronotum more parallel sided, only slightly arcuate, southern California…E. gracilis distans
64 Body usually flattened, elytral punctures simple, in rows, and more minute, never caudate, pronotum widest at middle, luster dull, Texas…E. knullorum
64’ Body usually not flattened, punctures variable, caudate or not, pronotum variable, if widest at middle then luster shiny, widespread…65
65 Elytral punctures irregular and strongly muricate, never caudate…E. sponsa
65’ Elytral punctures in rows and with simple punctures, or slightly asperate punctures, mainly at the elytral apex, elytra usually caudate, at least in males…66
66 Anterolateral angles of pronotum facing straight forward or only slightly projected outwards, hind angles not rounded, males caudate and with the metatibia sinuate, southern Arizona…E. eschscholtzii eschscholtzii
66’ If in southern Arizona then anterolateral angles of pronotum projecting outwards, or hind angles of pronotum appearing quite rounded…67
67 Hind angles of pronotum appearing rounded, size large, elytra often inflated and strongly convex, or fairly parallel sided…68 (E. spinipes)
67’ Hind angles of pronotum not rounded or only slightly rounded, size medium to large, elytra never inflated, often parallel sided…69
68 Elytra more or less parallel sided, west of the Pecos River…E. spinipes macrura
68’ Elytra ventricose, east of the Pecos River…E. spinipes ventricosa
69 Elytra caudate or strongly attenuate, punctures smaller, El Paso region…E. tenuipes
69’ Elytra at most slightly attenuate, punctures larger…E. gracilis gracilis
70 Elytra with conspicuous setae…71
70’ Elytra glabrous, or only with short inconspicuous setae…75
71 Size less than 12mm, elytra shiny with complex sculpturing and covered in golden hairs, areas with sandy soils around the Four Corners…E. barbata
71’ Size usually small but rarely less than 12mm, elytra usually dull, sometimes shiny, never with golden hairs, usually in deserts above the Sonoran Desert…72
72 Size larger, body more robust, northern Arizona and southern Utah…E. halli
72’ Size smaller, body more slender, generally around the Great Basin or the Great Sand Dunes of Colorado…73
73 Endemic to the Great Sand Dunes National Park…E. hirtipennis
73’ Distributed generally around the Great Basin…74
74 Setae black, generally around the Great Basin…E. letcheri
74’ Setae brownish, in and around Utah…E. aspera
75 Elytra flat and widened, about the same width as and meeting with pronotum to form a continuous line…76
75’ Elytra usually not flat or widened, and never meeting with pronotum to form a line, elytra elongate or ovate…80
76 Body covered in minute setae, elytra with rows of tubercules, widespread…E. tricostata
76’ Body glabrous, elytra lacking rows of tubercules, Texas, Oklahoma, and New Mexico…77
77 Elytral sculpturing rough, striae vague to absent, luster generally dull…E. neomexicana
77’ Elytra with clear striae, luster shiny…78
78 Elytra with deeply impressed striae…E. pedinoides
78’ Elytra with slightly impressed striae…79 (E. wenzeli)
79 Punctures of elytra fine but easily noticeable…E. wenzeli speculicollis
79’ Punctures of elytra extremely fine and minute…E. wenzeli wenzeli
80 Both elytra with around three large smooth costae, legs often dark red, southern Utah…E. parowana
80’ Both elytra without at least three large costae…81
81 Body elongate, elytra appearing smooth with minute muricate punctures, each puncture with a tiny seta arising from it, entire tarsus covered heavily with long setae, anterolateral angles of pronotum projected and acute, western Nevada…E. inornata
81’ Tarsi never entirely and heavily setose, at most only with short sparse setae, or some interrupting the plantar groove, elytra and pronotum variable, but if in Nevada then anterolateral angles not projected and acute…82
82 Elytral punctures muricate or scabrous, usually appearing rough, body elongate, elytra parallel sided and with not particularly attenuate, luster usually dull…E. nigrina (continuation)
82’ Punctures variable, if elytra appear rough then body not particularly elongate, and elytra more arcuate and attenuate…83
83 Size small, elytral luster generally shiny, elytra heavily punctate, usually irregular, never with tubercules, pronotal punctures small and sparse…E. extricata (continuation)
83’ Size small to medium, luster variable although generally dull if elytra with irregular punctures, said irregular punctures also smaller, elytra with punctures in rows or irregular, or with tubercules, papillae, or rugae…84
84 Larger protibial spur extending almost to third tarsomere, pronotum broader than long, elytra with small, granulate tubercules, luster dull, Pacific Northwest except southeast Oregon…E. humeralis
84’ Larger protibial spur never reaching this size if in the region stated above, but may be of this size if outside that region including southeast Oregon, if elytra tuberculate then tubercules larger and luster shiny…85
85 Elytra with papillae, pronotum wide, luster dull, California…E. papillosa
85’ Elytra without papillae, luster variable…86
86 Elytra with coarse, transverse, tuberculate rugae, luster shiny…E. corvina
86’ Elytra without transverse rugae, tuberculate or not, luster variable…87
87 Elytra tuberculate, tubercules larger, elytra noticeably rough, protibial spurs smaller…88
87’ Elytra not tuberculate, or if so then tubercules smaller, elytra less rough, and protibial spurs larger…89
88 Pronotum more or less arcuate and wider than long…E. granulata
88’ Pronotum more or less parallel sided and longer than wide…E. subtuberculata
89 Size small, pronotum evenly arcuate, punctures minute and in rows, luster usually dull, body never elongate, Arizona and New Mexico…E. arcuata
89’ Size variable, pronotum variable, but if evenly arcuate, then punctures more conspicuous, luster variable…90
90 Luster shiny, pronotum evenly arcuate, elytral punctures usually fairly large and in rows, outer protibial spur clearly larger than inner protibial spur, body usually ovate…E. debilis
90’ Luster variable, pronotum variable, punctures variable but rarely large, if protibial spurs disproportionate in size then luster more dull and elytra with tubercules or smaller punctures and a more elongate form…91
91 Longer protibial spur extending to almost to the third tarsomere, elytra with small to moderately sized tubercules, either in rows or irregular…92 (E. rileyi)
91’ Longer protibial spur extending only to apex of the first tarsomere, elytra never tuberculate…93
92 Elytra shiny with prominent striae, Four Corners…E. rileyi reducta
92’ Elytra dull without very prominent striae, widespread…E. rileyi rileyi
93 “…longer protibial spur parallel sided in basal half then tapering to a point at apex,” luster dull, punctures irregular if in California, if not then punctures in rows…94
93’ “…longer protibial spur evenly tapering to a point from base to apex,” luster usually shiny, sometimes dull, punctures variable, if in California then luster usually dull and punctures with some semblance of rows…96 (E. carbonaria)
94 Elytral punctures irregular, San Francisco region…E. quadricollis
94’ Elytral punctures organized in rows, generally around southeast Arizona…95 (E. anthracina)
95 Size larger, elytral punctures less fine, widespread…E. anthracina anthracina
95’ Size smaller, elytral punctures more fine, Chiricahua Mountains…E. anthracina lustrans
96 Strial punctures and those of intervals subequal in size, often diffusing, restricted to California…E. carbonaria omissa
96’ Punctures variable, but if in California then strial punctures larger than those of intervals and in rows…97
97 Body usually fairly fusiform, punctures conspicuous and in rows, east of the Pecos River and always below the southernmost edge of Arizona and New Mexico’s border…E. carbonaria soror
97’ Body only rarely fusiform, punctures variable, west of the Pecos River, or if not then above the southernmost edge of Arizona and New Mexico’s border…98
98 Punctures of elytra simple…100
98’ Punctures of elytra muricate…99
99 Strial punctures and those of intervals subequal in size, often diffusing, generally around northwest New Mexico…E. carbonaria knausii
99’ Strial punctures larger than those of intervals, striae in rows, often in ridges, widespread…E. carbonaria obsoleta
100 Body usually more fusiform, punctures more minute, size larger than 17mm, southern Arizona and New Mexico…E. carbonaria chihuahuaensis
100’ Body usually not fusiform, punctures more conspicuous, size 17mm or smaller, widespread…E. carbonaria carbonaria
