identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
03C17C29FFFBFF8273BD7980925272BC.text	03C17C29FFFBFF8273BD7980925272BC.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile Latrielle	<div><p>Key to the Megachile Species of Montana</p><p>This key was written based on previous works by Mitchell (1924, 1926a, 1927a, 1927 b, 1934, 1935a, 1935 b, 1936, 1937a, 1937 b, 1937c, 1937d, 1962, 1980), Ivanochko (1979), Sheffield et al. (2011), and Bzdyk (2012) (see also Sheffield 2020) and includes both sexes of the species that have been documented in Montana, their possible color variants, as well as species we most expect (based on their distributions or expected spread) to eventually be found in the state. We suggest reading the Taxonomic Challenges before using the key for greater ease of use and better understanding.</p><p>Difficulties in identifying Megachile to species often arise with specimens that were old when collected (i.e., they display wing and mandibular wear), grimy specimens, and specimens with closed mandibles or leg positioning that may obscure characters. Specimens may be re-washed in hot water and soap to remove grime from setae or teeth and then carefully blow-dried. If the mandibles are closed, opening the mandibles of a relaxed specimen using a pin may be useful. Similarly, repositioning the legs away from the body of a relaxed specimen can help for viewing certain characters, especially in males, as can extending/separating the individual tergites from one another to reveal the basal half, especially tergite 6 from tergite 5, in females.</p><p>The genus Megachile is characterized by having two submarginal cells subequal in length, no arolium between the tarsal claws, a labrum that is longer than wide, an apically depressed first metasomal tergite, and 3-jointed maxillary palpi. Females display scopa on the sternites, and males display a preapical carina on tergite 6 (Mitchell 1934; Michener 2007; Burrows et al. 2021). Users should refer to Michener, McGinley, and Danforth (1994) to first identify specimens to the genus Megachile . Entomological terms follow Torre-Bueno (1989). Certain species key out multiple times to account for variation in characters.</p><p>Abbreviations used in key</p><p>S 1– S 6: Sternites on the ventral surface of the metasoma.</p><p>T 1– T 6: Tergites on the dorsal surface of the metasoma.</p><p>Key to Megachile species of Montana: female specimens (i.e., 10 flagellomeres, 6 tergites)</p><p>1 Metasomal sternites with white apical setal bands between scopal setae (Fig. 6A); T2 with lateral, ovate fovea........... 2</p><p>- Metasomal sternites without white apical setal bands between scopal setae; T2 without lateral, ovate fovea.............. 3</p><p>2 S5 scopal setae all black; clypeal margin with small median tubercle (Fig. 6D); T3 with lateral, ovate fovea................................................................................. Megachile (Eutricharaea) apicalis Spinola</p><p>- S5 scopal setae white, sometimes apical half with black setae; clypeal margin without median tubercle, essentially straight; T3 without lateral, ovate fovea........................................ Megachile (Eutricharaea) rotundata (Fabricius)</p><p>[Note: Megachile (Eutricharaea) pusilla Pérez also keys out at 2’. This species has not been recorded from Montana but is an introduced species that could potentially occur in the state. Megachile pusilla has black setae laterally on T5–6 at most, while M. rotundata has black setae laterally on T2–6.]</p><p>3 Metasoma rounded in dorsal view, T2–3 widest, then narrowing from T4–6 (Fig. 6B)............................... 4</p><p>- Metasoma subparallel in dorsal view, T2–4 subequal in width (Fig. 6C)......................................... 32</p><p>4 Tergites without white apical setal bands; T1–2 covered in pale yellow to white pubescence contrasting entirely dark pubescence on T3–5............................................................................................. 5</p><p>- Most tergites with white apical setal bands; T1–2 sometimes with pale pubescence, but T3–5 without entirely black pubescence.......................................................................................... 7</p><p>5 S2–6 scopal setae orange; T6 usually with pale appressed setae............. Megachile (Xanthosarus) melanophaea Smith</p><p>[Note: Megachile (Xanthosarus) circumcincata (Kirby) also keys out at 5. This species has not been recorded from Montana but could potentially occur in the state. Megachile circumcincta has entirely pale pubescence on the ventral mesosoma and coxae, whereas Megachile melanophaea has dark pubescence on the ventral mesosoma and coxae.]</p><p>- S 2–6 scopal setae reddish-brown to black; T 6 usually with dark appressed setae.................................... 6</p><p>6 Basal mandibular tooth truncate (Fig. 7E); mandible from lateral view square basally, with parallel sides for a distance as long as wide, then tapering apically (Fig. 6J); S 2–6 scopal setae reddish-brown to black.................................................................................................... Megachile (Xanthosarus) gemula Cresson</p><p>- Basal mandibular tooth pointed (Fig. 7B); mandible from lateral view gradually tapering in width towards apex (Fig. 6I); S 2–6 scopal setae entirely black...................................... Megachile (Megachiloides) subnigra Cresson (part)</p><p>7 S 2–4 scopal setae entirely black.................................. Megachile (Megachiloides) subnigra Cresson (part)</p><p>[Note: There is a pale form of M. subnigra that has not been recorded from Montana but could potentially occur in the state. This form has all white scopal setae, T 6 straight in lateral profile, and 4-toothed mandibles without basal tooth with an angulation appearing as a weak additional tooth (i.e., appearing 5-toothed).]</p><p>[Note: Rare, melanistic forms of Megachile (Megachiloides) anograe Cockerell (S 2–6 scopal setae black) also key out at 7 but have 3-toothed mandibles (4-toothed in M. subnigra). This form has not been recorded from Montana.]</p><p>- S 2–4 scopal setae usually white, yellow, or orange........................................................... 8</p><p>8 Mandible 3-toothed (Fig. 7A)............................................................................ 9</p><p>- Mandible 4- (Figs. 7B–E) or 5-toothed (Figs. 7F–H)........................................................ 10</p><p>9 T 6 smooth and shiny, with punctures 3–5 diameters apart................. Megachile (Megachiloides) anograe Cockerell</p><p>- T 6 pitted and dull, with punctures ≤ 1 diameter apart.................... Megachile (Megachiloides) pascoensis Mitchell</p><p>10 S 6 scopal setae mostly (greater than 75%) pale, ivory to orange (can have black setae apically on S 6) ( M. mendica can approach ca. 50% black setae apically)........................................................................... 11</p><p>- S 6 scopal setae mostly (greater than 75%) dark, brown to black ( M. casadae and M. texana can approach ca. 50% pale setae basally)............................................................................................ 22</p><p>[Note: Setal coloration can be an unreliable character, as it can change or fade with time. Coloration can also vary intraspecifically, and specimens with questionable coloration can be keyed out in both directions.]</p><p>11 Mandibles 5-toothed, with deepest emargination between tips of 3 rd and 4 th tooth, emargination strongly angled towards 4 th tooth (Fig. 7F)........................................................................................... 12</p><p>- Mandibles 4- or 5-toothed, with emarginations between all teeth similar in depth (Figs. 7B–E, G–H).................. 13</p><p>12 T 3–5 with apical setal bands consistently wide, as wide medially as laterally; T 1–2 usually covered in white pubescence; T 6 with appressed pale setae............................................ Megachile (Xanthosarus) dentitarsus Sladen</p><p>- T 3–5 with apical setal bands inconsistent in width, wider laterally than medially, often incomplete; T 1–2 usually covered in yellow pubescence; T 6 with appressed yellow to orange setae............................................................................... Megachile (Xanthosarus) latimanus Say and Megachile (Xanthosarus) perihirta Cockerell</p><p>[Note: The females of M. latimanus and M. perihirta cannot be reliably separated in Montana based on morphology. See Taxonomic Challenges in results above.]</p><p>13 Basal mandibular tooth truncate (Fig. 7E); T 6 setae dark brown to black........... Megachile (Xanthosarus) frigida Smith</p><p>- Basal mandibular tooth rounded or pointed (Fig. 7B–D, G–H); T 6 setae color variable............................. 14</p><p>14 Mandibles without cutting edge ventrad the tooth plane (Fig. 7H); mandible surface with elevated ridge running diagonally from apex of 2 nd tooth to the dorsal point of mandibular attachment (Fig. 7H)..... Megachile (Megachile) montivaga Cresson</p><p>- Mandibles with cutting edge ventrad the tooth plane, sometimes only present as small, angled edge (Figs. 7B–G); mandible surface without elevated ridge.......................................................................... 15</p><p>15 Mandibles 4-toothed (sometimes basal tooth with angulation appearing as a weak additional tooth [i.e., appearing 5-toothed]) (Figs. 7B, 7D)....................................................................................... 16</p><p>- Mandibles 5-toothed (Fig. 7G).......................................................................... 20</p><p>16 Clypeal margin with two broadly incurved emarginations (Fig. 6E); tarsi and basitarsus reddish brown, contrasting black tibia.................................................................... Megachile (Sayapis) mellitarsis Cresson</p><p>- Clypeal margin without two broad emarginations; tarsi and basitarsus brown to black, not contrasting tibia............. 17</p><p>17 S 6 upcurved at the tip, extending beyond T 6 (Fig. 7L); T 6 straight in lateral profile with pale, velvety, appressed setae (Fig. 7L)................................................................. Megachile (Argyropile) parallela Smith</p><p>- S 6 not upcurved or extending beyond T 6 (Fig. 7I–K, M–N)................................................... 18</p><p>18 T 6 convex basally and concave apically in a “pinched shape” in lateral profile (Fig. 7K); mandibles with 4 distinct teeth (Fig. 7B)................................................................... Megachile (Litomegachile) brevis Say</p><p>- T 6 straight in lateral profile (Fig. 7J); mandibles 4-toothed, basal tooth with angulation appearing as a weak additional tooth [i.e., appearing 5-toothed]............................................................................. 19</p><p>19 T 6 with pale appressed setae........................................... Megachile (Litomegachile) snowi Mitchell</p><p>- T 6 with brown appressed setae........................................ Megachile (Litomegachile) mendica Cresson</p><p>20 Body size 17–20 mm long; clypeus shiny and sparsely punctate medially (punctures 1–3 diameters apart); clypeal margin with four prominent tubercles.............................................. Megachile (Megachile) inermis Provancher</p><p>- Body size 9–12 mm long; clypeus densely punctate medially (punctures ≤ 1 diameter apart); clypeal margin irregular, without prominent tubercles.................................................................................. 21</p><p>21 T 6 with black setae.............................................. Megachile (Megachile) centuncularis (Linnaeus)</p><p>- T 6 with golden setae.................................................... Megachile (Megachile) relativa Cresson</p><p>22 T 2 in dorsal view with lateral, erect black setae............................................................ 23</p><p>- T 2 in dorsal view without lateral, erect black setae.......................................................... 24</p><p>23 T 3–5 strongly concave medially between surrounding apical and basal grooves, when viewed from lateral profile (Fig. 7O); ocellocular distance shorter than ocelloccipital distance (Fig. 8J)........... Megachile (Megachiloides) dakotensis Mitchell</p><p>- T 3–5 flat to slightly concave medially, with no prominent apical or basal grooves; ocellocular distance longer than ocelloccipital distance (Fig. 8L).................................................... Megachile (Litomegachile) texana Cresson</p><p>24 Clypeus shiny and sparsely punctate medially (punctures 2–3 diameters apart), becoming more densely punctate laterally.................................................................. Megachile (Megachiloides) casadae Cockerell</p><p>- Clypeus with dense punctation medially and laterally (punctures ≤ 1 diameter apart)............................... 25</p><p>25 Mandibles 5-toothed (Fig. 7G) OR mandibles 4-toothed, basal tooth with angulation appearing as a weak additional tooth (i.e., appearing 5-toothed) (Fig. 7D).......................................................................... 26</p><p>- Mandibles distinctly 4-toothed (Figs. 7B–C)............................................................... 27</p><p>26 S 5 scopal setae black, at least apically; mandibles 5-toothed (Fig. 7G)......... Megachile (Megachile) lapponica Thomson</p><p>- S 5 scopal setae white; mandibles 4-toothed with basal mandiblular tooth angulate, appearing as a weak additional tooth (i.e., 5-toothed) (Fig. 7D)................................................. Megachile (Litomegachile) gentilis Cresson</p><p>27 Mandibles with asymmetrical emargination between tips of 3 rd and 4 th tooth, emargination deepest closer to 4 th tooth (Fig. 7C) AND mandible from lateral view gradually tapering in width towards apex (Fig. 6I)............................... 28</p><p>- Mandibles with semicircular, symmetrical emargination between tips of 3 rd and 4 th tooth (Fig. 7B) AND mandible from lateral view square basally, with sides parallel for approximately ⅓ the length of mandible, then tapering apically (Fig. 6K)..... 30</p><p>28 T 5 with punctures 2–4 diameters apart medially, surface polished and shiny... Megachile (Megachiloides) wheeleri Mitchell</p><p>- T 5 with punctures ≤ 1 diameter apart medially, surface matte to shiny........................................... 29</p><p>29 S 5 scopal setae all white; area directly posterior of scutum center with variable punctation 1–2 diameters apart.......................................................................... Megachile (Megachiloides) nevadensis Cresson</p><p>- S 5 scopal setae at least partly black; area directly posterior of scutum center with consistently spaced punctures almost touching........................................................ Megachile (Megachiloides) manifesta Cresson</p><p>30 T 6 strongly convex basally and concave apically in a “pinched shape” in lateral profile (Fig. 7K).................................................................................. Megachile (Litomegachile) onobrychidis Cockerell</p><p>- T 6 concave apically in lateral profile (Figs. 7M–N)......................................................... 31</p><p>31 T 6 with suberect pale setae and erect black setae; T 6 concave apically in lateral profile (Fig. 7N); apical margin of clypeus with short median carina 2 times as long as diameter of median ocellus (Fig. 6G).... Megachile (Litomegachile) lippiae Cockerell</p><p>- T 6 with suberect and erect brown to black setae (sometimes with suberect pale setae in small patches laterally); T 6 slightly to moderately concave apically in lateral profile (Fig. 7M); apical margin of clypeus with long transverse carina 4 times as long as diameter of median ocellus (Fig. 6H).............................. Megachile (Litomegachile) coquilletti Cockerell</p><p>32 Genal margin with pronounced tooth posteriorly (Fig. 7P); clypeal margin with three tubercles.................................................................................................. Megachile (Sayapis) pugnata Say</p><p>- Genal margin without tooth posteriorly; clypeal margin variable............................................... 33</p><p>33 Mandibles without cutting edge ventrad the 2 nd and 3 rd tooth.................................................. 34</p><p>- Mandibles with cutting edge ventrad the 2 nd and 3 rd tooth..................................................... 35</p><p>34 In fresh specimens (as judged by a completely intact apical wing margin), T 5 white apical setal band mostly complete medially, similar in width and density to T 1–4 apical setal bands, individual setae thick and plumose; in all specimens, vertex of head with small and dense punctation (ca. 8–10 punctures between lateral ocelli and posterior margin of vertex); scutum and scutellum with similar punctation (close and evenly spaced); occipital suture smooth and shiny, impunctate................................................................................... Megachile (Chelostomoides) angelarum Cockerell</p><p>- In fresh specimens (as judged by a completely intact apical wing margin), T 5 white apical setal band incomplete medially, narrower and less dense than T 1–4 apical setal bands, individual setae thinner and less plumose; in all specimens, vertex of head with large, sparse punctation (ca. 4–6 punctures between lateral ocelli and posterior margin of vertex); scutum punctation close and evenly spaced compared to scutellum punctation, which is irregular and inconsistent; occipital suture with a line of punctures appearing as a slight carina........................... Megachile (Chelostomoides) campanulae (Robertson)</p><p>[Note: Megachile (Callomegachile) sculpturalis Smith keys out at 34’. This species has not been recorded from Montana but could potentially occur in the state. Megachile sculpturalis has a large body size (21–25 mm long), contrasting the much smaller body sizes of M. angelarum (10–11 mm long) and M. campanulae (10–12 mm long). Megachile sculpturalis also has yellow pubescence on T 1 with a white apical setal band and black apical setal bands on T 2–5, whereas M. angelarum and M. campanulae have white apical setal bands on T 2–5.</p><p>35 Clypeal margin with two broadly incurved emarginations (Fig. 6E).......... Megachile (Sayapis) mellitarsis Cresson (part)</p><p>[Note: Megachile (Sayapis) inimica Cresson also keys out at 35. This species has not been recorded from Montana but could potentially occur in the state. Megachile inimica has all red or all black legs, while M. mellitarsis has red tarsi contrasting with the black tibia.]</p><p>- Clypeal margin with two prominent, wide, lateral tubercles (at least as long as wide), surrounding median triangular tubercle (Fig. 6F)................................................................ Megachile (Sayapis) fidelis Cresson</p><p>Key to Megachile species of Montana: male specimens (i.e., 11 flagellomeres, 7 tergites)</p><p>1 Probasitarsus narrow, not excavated ventrally (Fig. 8A), often brown to black..................................... 2</p><p>- Probasitarsus usually widely expanded, excavated ventrally, (Fig. 8B), often white to yellow (except M. gemula which has an excavated, but narrow, dark brown to black probasitarsus).................................................... 19</p><p>2 T6 (anterior to the transverse carina, Fig. 9C–D) with tomentose, pale setae....................................... 3</p><p>- T6 (anterior to the transverse carina) bare or with sparse setae................................................ 12</p><p>3 T2 with lateral, ovate fovea............................................................................. 4</p><p>- T2 without lateral, ovate fovea........................................................................... 5</p><p>4 T3 with lateral, ovate fovea............................................ Megachile (Eutricharaea) apicalis Spinola</p><p>- T3 without lateral, ovate fovea...................................... Megachile (Eutricharaea) rotundata (Fabricius)</p><p>[Note: Megachile (Eutricharaea) pusilla also keys out at 4’. This species has not been recorded from Montana but is an introduced species that could potentially occur in the state. Megachile pusilla has a genal tooth posterior to the ventrad point of mandibular attachment that is longer than wide, whereas M. rotundata has a genal tooth that is as long as wide.]</p><p>5 T5 with white apical setal band, sometimes in depressed apical groove (sometimes reduced to lateral sides, as in M. coquilletti).......................................................................................... 6</p><p>- T5 without white apical setal band (may have some setae laterally)............................................. 11</p><p>6 T6 transverse carina deeply emarginate medially (Fig. 9A).................................................... 7</p><p>- T6 transverse carina weakly emarginate, often appearing as a continuous jagged edge (Fig. 9B).............................................................................................. Megachile (Litomegachile) brevis Say</p><p>7 Mandible 4-toothed; apical margin of T6 (ventrad the transverse carina) with two pairs of prominent teeth laterally (Fig. 9C)..................................................................... Megachile (Argyropile) parallela Smith</p><p>- Mandible 3-toothed; apical margin of T6 (ventrad the transverse carina) with two pairs of small teeth laterally (Fig. 9D).... 8</p><p>8 Protarsomeres 2–4 light to dark yellow............................... Megachile (Litomegachile) coquilletti Cockerell</p><p>- Protarsomeres 2–4 brown to black........................................................................ 9</p><p>9 Apical margin of T6 (ventrad the transverse carina) with submedian teeth closer to each other than to lateral teeth (Fig. 9E) or distances subequal................................................... Megachile (Litomegachile) snowi Mitchell</p><p>- Apical margin of T6 (ventrad the transverse carina) with submedian teeth closer to lateral teeth than to each other (Fig. 9F).................................................................................................... 10</p><p>10 Scutum with greater than 50% black pubescence (viewed laterally); tergites with significant bands of black pubescence (viewed laterally); vertex of head with greater than 50% black pubescence.............. Megachile (Litomegachile) texana Cresson</p><p>- Scutum with less than 25% black pubescence (viewed laterally); tergites with mostly white pubescence (viewed laterally); vertex of head with mostly white pubescence............................ Megachile (Litomegachile) lippiae Cockerell</p><p>11 T 4–5 somewhat dull, with punctures ca. 1 diameter apart.................... Megachile (Litomegachile) gentilis Cresson</p><p>- T 4–5 polished and shiny, with punctures 2–4 diameters apart................ Megachile (Litomegachile) mendica Cresson</p><p>12 S 4 not visible, retracted............................................................................... 13</p><p>- S 4 visible.......................................................................................... 14</p><p>13 Vertex of head with large, sparse punctation (ca. 4 punctures between lateral ocelli and posterior margin of vertex); small procoxal spine present but obscured by dense, plumose setae....... Megachile (Chelostomoides) campanulae (Robertson)</p><p>- Vertex of head with small and dense punctation (ca. 9 punctures between lateral ocelli and posterior margin of vertex); small procoxal spine visible amidst surrounding short setae................ Megachile (Chelostomoides) angelarum Cockerell</p><p>14 Procoxal spine present, may be reduced to a small nub and covered with small tuft of dense orange setae.............. 15</p><p>- Procoxal spine absent................................................................................ 18</p><p>15 Procoxal spine prominent, longer than wide............................................................... 16</p><p>- Procoxal spine nub-like, wider than long and covered with small tuft of dense orange setae......................... 17</p><p>16 Ocelloccipital distance greater than ocellocular distance (Fig. 8J); T 2–4 strongly depressed basally and apically (Fig. 10D)................................................................ Megachile (Megachiloides) dakotensis Mitchell</p><p>- Ocelloccipital distance less than ocellocular distance (Fig. 8L); T 2–4 moderately depressed basally but not depressed apically (Fig. 10E)................................................... Megachile (Litomegachile) onobrychidis Cockerell</p><p>17 Mandibular teeth unevenly spaced, 2 nd tooth closer to apical tooth; ocelloccipital distance longer than ocellocular distance (Fig. 8J); body size 11–16 mm long......................................... Megachile (Megachile) inermis Provancher</p><p>- Mandibular teeth evenly spaced from one another; ocelloccipital distance approximately subequal to (Fig. 8K) or shorter than (8L) ocellocular distance; body size 9–11mm long......................... Megachile (Megachile) montivaga Cresson</p><p>18 Clypeal margin with small triangular median tubercle..................................................................................... Megachile (Megachile) lapponica Thomson and Megachile (Megachile) relativa Cresson</p><p>[Note: The males of Montana M. lapponica and M. relativa cannot be reliably separated based on morphology. See Taxonomic Challenges in results above.]</p><p>- Clypeal margin without median tubercle............................ Megachile (Megachile) centuncularis (Linnaeus)</p><p>19 Mesobasitarsus with smooth, glabrous protuberance ventrally (Figs. 8C–D); mesotibia without apical spur (Figs. 8C–D); mesofemur widely enlarged, at least 2 times as wide as mesotibia.............................................. 20</p><p>- Mesobasitarsus without protuberance ventrally (Fig. 8E); mesotibia with apical spur (Fig. 8E); mesofemur about 1.5 times as wide as mesotibia................................................................................... 22</p><p>20 Ventral mesepisternum (from ventral view of mesosoma, directly anterior to mesocoxa) with small spine................................................................................ Megachile (Xanthosarus) dentitarsus Sladen</p><p>- Ventral mesepisternum (from ventral view of mesosoma, directly anterior to mesocoxa) with smooth, spineless carina.... 21</p><p>21 Mesobasitarsus from anterior view with narrowly rounded, ventral protuberance basally (Fig. 8D); ventral side of mesofemur smooth and convexly rounded....................................... Megachile (Xanthosarus) perihirta Cockerell</p><p>- Mesobasitarsus from anterior view with wide, rounded, ventral protuberance basally (Fig. 8C); ventral side of mesofemur widely depressed..................................................... Megachile (Xanthosarus) latimanus Say</p><p>22 Mandibles 4-toothed................................................................................. 23</p><p>- Mandibles 3-toothed................................................................................. 25</p><p>23 Profemur with two brown stripes ventrally.................................. Megachile (Xanthosarus) frigida Smith</p><p>- Profemur without two brown stripes ventrally (often one stripe occurs on M. circumcincta)......................... 24</p><p>24 Dorsal face of protibia with posterior angle acute, apex entirely dark........... Megachile (Xanthosarus) gemula Cresson</p><p>[Note: Megachile (Xanthosarus) circumcincta (Kirby) also keys out at 24. This species has not been recorded from Montana but could potentially occur in the state. Megachile circumcincta has a white apical setal band on T 5 (absent in M. gemula) and often has one brown stripe on the ventral profemur. The dorsal face of the protibia of M. circumcincta has an acute posterior angle as in M. gemula, but the apex is yellow, whereas the apex of the protibia of M. gemula is dark brown to black.]</p><p>- Dorsal face of protibia with posterior angle rounded and spatulate, apex entirely pale............................................................................................... Megachile (Xanthosarus) melanophaea Smith</p><p>25 Procoxal spine thin and narrowly pointed (Fig. 8H)......................................................... 26</p><p>- Procoxal spine wide and spatulate (Fig. 8I)............................................................... 28</p><p>26 Protarsi distinctly yellow; front basitarsus with elongated apical dilation reaching apex of 3 rd tarsomere.................................................................................... Megachile (Sayapis) mellitarsis Cresson</p><p>- Protarsi white or pale yellow to dark brown; front basitarsus with apical dilation not reaching 3 rd tarsomere............ 27</p><p>27 Probasitarsus along basal ⅓ of posterior edge of scoop-shaped dilation with dark setae.... Megachile (Sayapis) pugnata Say</p><p>- Probasitarsus along entire posterior edge of scoop-shaped dilation with dark setae..... Megachile (Sayapis) fidelis Cresson</p><p>[Note: Megachile (Sayapis) inimica Cresson also keys out at 27’. This species has not been recorded from Montana but could potentially occur in the state. Megachile inimica has a patch of short, suberect setae at the base of the procoxal spine (setae shorter than flagellomere 1), whereas M. fidelis has a few long, erect setae (setae longer than flagellomere 1) at the base of the procoxal spine.]</p><p>28 Genal margin directly posterior to the ventral mandibular attachment with tooth as-long-as or longer-than-wide (the prolegs may need to be repositioned to see this character) (Fig. 10H)................................................. 29</p><p>- Genal margin directly posterior to the ventral mandibular attachment without obvious tooth, often with a tuft of setae (Fig. 10I).............................................................................................. 31</p><p>29 Procoxal spine with short, suberect setae in patch at base............... Megachile (Megachiloides) nevadensis Cresson</p><p>- Procoxal spine without patch of setae at base.............................................................. 30</p><p>30 Ventral mesepisternum (from ventral view of mesosoma, directly posterior to the procoxal spine) with smooth, rounded carina, not protruding; metatarsomeres triangular from lateral view (Fig. 8F)....... Megachile (Megachiloides) manifesta Cresson</p><p>- Ventral mesepisternum (from ventral view of mesosoma, directly posterior to the procoxal spine) with protruding triangular carina; metatarsomeres quadrate from lateral view (Fig. 8G)............... Megachile (Megachiloides) wheeleri Mitchell</p><p>31 Pubescence on meso- and metalegs mostly black........................ Megachile (Megachiloides) subnigra Cresson</p><p>- Pubescence on meso- and metalegs mostly pale............................................................ 32</p><p>32 Clypeal margin emarginate medially and laterally (Figs. 10A–B).............................................. 33</p><p>- Clypeal margin mostly straight, with slight emargination medially (Fig. 10C)...................................................................................................... Megachile (Megachiloides) casadae Cockerell</p><p>33 Clypeal margin with deep U-shaped median emargination (as deep as wide) (Fig. 10A); S 5 narrowly rimmed apicomedially with dark brown setae (Fig. 10F); metafemur with hint of pale fovea dorsally.................................................................................................... Megachile (Megachiloides) pascoensis Mitchell</p><p>- Clypeal margin with wide, shallow median emargination (2–3 times as wide as deep) (Fig. 10B); S 5 with black apicomedial setal patch (Fig. 10G); metafemur with distinct, elongate, brown fovea dorsally.................................................................................................... Megachile (Megachiloides) anograe Cockerell</p><p>[Note: Megachile (Callomegachile) sculpturalis (Smith) also keys out at 33’. This species has not been recorded from Montana but is an introduced species that could potentially occur in the state. Megachile sculpturalis has extremely large, unevenly-spaced punctures on T 2–3, T 2–4 basally depressed, T 2–5 without white apical setal bands, a carinate genal margin, a large body size (&gt; 20 mm long), and lacks dorsal fovea on the metafemur as seen in M. anograe . Megachile anograe has white apical setal bands on T 1–4, lacks a carinate genal margin, and is smaller (10–11 mm long) than M. sculpturalis .]</p></div>	https://treatment.plazi.org/id/03C17C29FFFBFF8273BD7980925272BC	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF0FF8373BD7ED4919571B1.text	03C17C29FFF0FF8373BD7ED4919571B1.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Chelostomoides) angelarum Cockerell 1902	<div><p>Megachile (Chelostomoides) angelarum Cockerell, 1902</p><p>Megachile angelarum Cockerell, 1902: 70 . Burkle et al. 2020: 7.</p><p>Megachile (Chelostomoides) angelarum; Mitchell 1937d: 386; 1956: 131. Sheffield et al. 2011: 26. Kuhlman and Burrows 2017: 12. Reese et al. 2018: 21. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 69.</p><p>Chalicodoma (Chelostomoides) angelarum (Cockerell); Butler 1965: 15. Hurd 1979: 2073.</p><p>Diagnosis. The female of M. angelarum can be recognized by its subparallel metasoma (viewed dorsally) (Fig. 6C), mandibles without cutting edges, clypeal margin that is medially emarginate and laterally crenulate, white T5 apical setal band which is similar in width and appearance to the T1–4 apical setal bands, vertex of head with small, dense punctation (ca. 8–10 punctures between lateral ocelli and posterior margin of vertex), and a smooth, shiny, impunctate occipital suture. The female of M. angelarum is most similar to M. campanulae, which has a medially incomplete T5 white apical setal band that is thinner and less plumose than those on T1–4, and large, sparse punctation on the vertex of head (ca. 4–6 punctures between lateral ocelli and posterior margin of vertex) (see Taxonomic Challenges). The male of M. angelarum can be distinguished by its retracted S4 and dense punctation on the vertex of the head (ca. 9 punctures between lateral ocelli and posterior margin of vertex). Male M. angelarum are most similar to M. campanulae, which have large, sparse punctation on the vertex of the head (ca. 4 punctures between lateral ocelli and posterior margin of vertex).</p><p>Notes. These mason bees use plant resins, not leaves, to construct nest cells in existing cavities and are therefore not leafcutting bees. This species was first recorded in the published literature from Montana in 2017 from Missoula County, though the earliest recorded specimen year is 2015 (Kuhlman &amp; Burrows 2017; Table 1). It is now known from five counties in Western Montana (Fig. 1A). For further details on identification issues see Taxonomic Challenges. Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFF0FF8373BD7ED4919571B1	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF0FF8473BD7A6191957400.text	03C17C29FFF0FF8473BD7A6191957400.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) anograe Cockerell 1908	<div><p>Megachile (Megachiloides) anograe Cockerell, 1908</p><p>Megachile anograe Cockerell, 1908: 261 . Adhikari et al. 2019: Supplementary Table S4.</p><p>Megachile (Derotropis) anograe; Mitchell 1936: 158; 1944: 142. Hurd 1979: 2062. Ivanochko 1979: 257.</p><p>Megachile (Megachiloides) anograe; Raw 2002: 16. Scott et al. 2011: 55. Sheffield et al. 2011: 52. Delphia et al. 2019a: 25.</p><p>Megachile (Derotropis) laurita Mitchell, 1927a: 115; 1936: 160.</p><p>Megachile (Megachiloides) laurita: Raw 2002: 18.</p><p>Megachile (Xeromegachile) alamosana Mitchell, 1934: 329 .</p><p>Megachile (Derotropis) alamosana; Mitchell 1936: 158; 1937a: 330; 1944: 142.</p><p>Megachile (Megachiloides) alamosana; Raw 2002: 16. Scott et al. 2011: 55.</p><p>Diagnosis. The female of M. anograe can be distinguished by its 3-toothed mandibles (Fig. 7A) and a smooth and shiny T6 with well-separated punctures (3–5 diameters apart). For information on the rare melanistic form (not seen in Montana) see Taxonomic Challenges. In Montana, females of this species are only likely to be confused with M. pascoensis, which also has 3-toothed mandibles, but in M. pascoensis T6 is pitted and dull with closely spaced punctures (≤ 1 diameter apart). The male of M. anograe can be distinguished by its wide and spatulate procoxal spine (Fig. 8I), medially and laterally emarginate clypeus (Fig. 10B), fovea on the dorsal metafemur, and apicomedial setal patch on S5 (Fig. 10G). Males of M. anograe are most similar to M. pascoensis, but the clypeal margin is much more deeply emarginate medially in M. pascoensis (Fig. 10A). For further details on identification issues see Taxonomic Challenges.</p><p>Notes. At the continental scale, M. anograe and M. pascoensis are in general allopatric, with M. anograe east of the continental divide and M. pascoensis to the west. This division so far holds in Montana. Megachile anograe is the more common of the two in Montana, occurring in the drier southern and central counties east of the divide (Fig. 1B) while the rarer M. pascoensis is known only from the wetter northwest Montana west of the divide (Fig. 1 AA). Sheffield et al. (2011) report melanistic forms in the western U.S., though we did not find them in Montana. Photographs, a full morphological description, and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFF0FF8473BD7A6191957400	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF7FF8473BD7EF1934A7102.text	03C17C29FFF7FF8473BD7EF1934A7102.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Eutricharaea) apicalis Spinola 1808	<div><p>Megachile (Eutricharaea) apicalis Spinola, 1808</p><p>Megachile apicalis Spinola, 1808: 259 .</p><p>Megachile (Eutricharaea) apicalis; Mitchell 1962: 120. Hurd 1979: 2057. Cooper 1984: 225. Sheffield et al. 2011: 29. Kuhlman and Burrows 2017: 12. Reese et al. 2018: 21. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 69.</p><p>Megachile virginiana Mitchell, 1926a: 113 .</p><p>Diagnosis. The female of M. apicalis can be identified by the white apical setal bands on S2–6 (Fig. 6A), black scopal setae on S5, and lateral, ovate fovea on T2 and T3. Females of M. apicalis are most similar to M. rotundata, which have white scopal setae on S5 and lateral, ovate fovea on T2 only. The male of M. apicalis can be distinguished by the lateral, ovate fovea on T2 and T3. Males of M. apicalis are most similar to M. rotundata, which have lateral, ovate fovea on T2 only.</p><p>Notes. Megachile apicalis is an accidentally introduced species in the United States, first collected in Montana in 2013 from localities in Deer Lodge, Sanders, and Lake Counties. It was first documented in the literature by Kuhlman &amp; Burrows (2017). This species may contribute to pollination of the invasive yellow star-thistle ( Centaurea solstitialis), though not as strongly as A. mellifera (Barthell et al. 2001) . Megachile apicalis is currently present in western Montana but is expected to spread further (Fig. 1C). It is established on both coasts of the U.S. and seems to be moving into Montana from the Pacific Northwest region (see Discussion: Notes on Megachile (Eutricharaea) rotundata and Introduced Megachile Species). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFF7FF8473BD7EF1934A7102	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF7FF8473BD7BFE9444723A.text	03C17C29FFF7FF8473BD7BFE9444723A.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) brevis Say 1837	<div><p>Megachile (Litomegachile) brevis Say, 1837</p><p>Megachile brevis Say, 1837: 407 . O’Neill and Seibert 1996: 321. Pearce 2008: 51, 107. Drons 2012: 58. Pearce et al. 2012: 101. Adhikari et al. 2019: Supplementary Table S4.</p><p>Megachile (Litomegachile) brevis; Mitchell 1935a: 13; 1962: 114. Butler 1965: 2. Hurd 1979: 2051. Ivanochko 1979: 78. Fultz 2005: 134. Gonzalez 2008: 35. Scott et al. 2011: 55. Sheffield et al. 2011: 33. Bzdyk 2012: 37. Kuhlman and Burrows 2017: 12. Reese et al. 2018: 21. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Megachile brevis var. nupta; Mitchell 1935a: 13.</p><p>Diagnosis. The females of M. brevis can be identified by the usually all pale yellowish white scopal setae on S2–S6 (except occasionally black scopal setae on the apical half of S6; see Taxonomic Challenges), 4-toothed mandibles with an even, semicircular emargination between the 3 rd and 4 th teeth (Fig. 7B), appressed white setae on T6, and the “pinched shape” of T6, which is convex basally and concave apically (viewed laterally) (Fig. 7K). The females of M. brevis are most similar to M. onobrychidis, which has entirely black scopal setae on S6 and black setae on T6. For further details on identification issues see Taxonomic Challenges. The males of M. brevis can be identified by the narrow probasitarsus, which is not excavated ventrally (Fig. 8A), tomentose, white setae on T6, and weakly emarginate transverse carina on T6 (Fig. 9B).</p><p>Notes. Megachile brevis is a commonly collected species found widely in Montana (Fig. 1D) that nests in a variety of substrates (Sheffield et al. 2011). Photographs, illustrations, full morphological descriptions, and notes on the biology of this species can be found in Sheffield et al. (2011) and Bzdyk (2012).</p></div>	https://treatment.plazi.org/id/03C17C29FFF7FF8473BD7BFE9444723A	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF6FF8573BD7FD0920871DF.text	03C17C29FFF6FF8573BD7FD0920871DF.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Chelostomoides) campanulae (Robertson 1903)	<div><p>Megachile (Chelostomoides) campanulae (Robertson, 1903)</p><p>Oligotropus campanulae Robertson, 1903: 171 .</p><p>Megachile (Chelostomoides) campanulae; Mitchell 1934: 301; 1937d: 389; 1956: 136; 1962: 182. Raw 2002: 7. Gonzalez 2008: 37. Scott et al. 2011: 54. Sheffield et al. 2011: 28. Drons 2012: 58. Reese et al. 2018: 21. Delphia et al. 2019a: 24.</p><p>Chalicodoma (Chelostomoides) campanulae; Hurd 1979: 2073.</p><p>Megachile campanulae; Burkle et al. 2020: 7.</p><p>Chelosomoides (Chelosomoides) campanulae; Engel 2020: 10.</p><p>Oligotropus wilmingtoni Mitchell, 1924: 156 .</p><p>Megachile angelarum, not Cockerell, 1902 (misidentification); Reese et al. 2018: 21. Delphia et al. 2019b: 24. Burkle et al. 2020: 7. LaManna et al. 2020: Supplementary Material pg. 40.</p><p>Diagnosis. The female of M. campanulae can be identified by its subparallel metasoma (viewed dorsally) (Fig. 6C), mandibles without cutting edges, clypeal margin that is medially emarginate and laterally crenulate, a medially incomplete T5 apical setal band that is thinner and less plumose than T1–4 apical setal bands, vertex of head with large, sparse punctation (ca. 4–6 punctures between lateral ocelli and posterior margin of vertex), close and evenly spaced scutum punctation compared to irregular and inconsistent scutellum punctation, and a line of punctures on the occipital suture appearing as a slight carina. Females of M. campanulae are most similar to M. angelarum (see M. angelarum above) (see Taxonomic Challenges). The male of M. campanulae can be identified by its retracted S4 and large, sparse punctation on the vertex of the head (ca. 4 punctures between lateral ocelli and posterior margin of vertex). Males of M. campanulae are most similar to M. angelarum (see M. angelarum above).</p><p>Notes. In Montana, M. campanulae has been collected in scattered western and eastern localities (Fig. 1E). These mason bees use plant resins, not leaves, to construct nest cells in existing cavities or trap nests (O’Neill &amp; O’Neill 2016) and are therefore not leafcutting bees. Because of misidentifications noted above in the synonymical table, the morphological description of the female in Sheffield et al. (2011) is not accurate. See Table 2, Supplementary Material 2: Erroneous Records, and Taxonomic Challenges for further explanation.The vouchers for the misidentified specimens (Reese et al. 2018; Burkle et al. 2020; LaManna et al. 2020) are in the Burkle Community Ecology Lab at Montana State University identified as female M. campanulae (5718LR, 19730CHS, 68812LR, 64728LR, 1725CHS, 73A817LR). The vouchers for the misidentified specimens (Delphia et al. 2019b) are in the O’Neill Research Collection at Montana State University identified as female M. campanulae (KMOC #1435, KMOC #1436, KMOC #1437) (Table 2).</p></div>	https://treatment.plazi.org/id/03C17C29FFF6FF8573BD7FD0920871DF	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF6FF8573BD7A4C910D7235.text	03C17C29FFF6FF8573BD7A4C910D7235.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) casadae Cockerell 1898	<div><p>Megachile (Megachiloides) casadae Cockerell, 1898</p><p>Megachile casadae Cockerell, 1898: 127 . Drons 2012: 58.</p><p>Megachile (Xeromegachile) casadae Cockerell; Mitchell 1934: 302; 1937a: 348; 1944: 136. Butler 1965: 7. Hurd 1979: 2063.</p><p>Megachile (Megachiloides) casadae Cockerell; Raw 2002: 17. Scott et al. 2011: 55. Sheffield et al. 2011: 54.</p><p>Megachile austinensis Mitchell, 1927a: 105 .</p><p>Diagnosis. The female of M. casadae can be identified by a shiny and sparsely punctate clypeus medially, 4-toothed mandibles with an asymmetrical emargination between the 3 rd and 4 th teeth that is deepest closer to the 4 th tooth (Fig. 7C), black scopal setae on S6, and T6 with an elevated ridge apicomedially (appears laterally “pinched” in dorsal profile), with dense brown setae along ridge directed medially. The male of M. casadae can be identified by 3-toothed mandibles, wide and spatulate procoxal spines (Fig. 8I), and a slight medial emargination in its otherwise mostly straight clypeal margin (Fig. 10C).</p><p>Notes. This species is a new state record for Montana. Megachile casadae is most common to the south of Montana (Fig. 1F) and reaches its northernmost extent in Montana, east of the divide, and southern Alberta. Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFF6FF8573BD7A4C910D7235	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF5FF8673BD7C4D91387031.text	03C17C29FFF5FF8673BD7C4D91387031.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) coquilletti Cockerell 1915	<div><p>Megachile (Litomegachile) coquilletti Cockerell, 1915</p><p>Megachile mendica coquilletti Cockerell, 1915: 535 .</p><p>Megachile (Litomegachile) coquilletti; Mitchell 1935a: 21. Butler 1965: 2. Hurd 1979: 2052. Ivanochko 1979: 93. Sheffield et al. 2011: 35. Bzdyk 2012: 41. Kuhlman and Burrows 2017: 12. Sheffield and Heron 2019: 70.</p><p>Diagnosis. The female of M. coquilletti can be distinguished by its moderately concave T6 (Fig. 7M) with brown to black setae (often with suberect pale setae in small patches laterally), 4-toothed mandibles with a semicircular, symmetrical emargination between the 3 rd and 4 th teeth (Fig. 7B), and long transverse medial carina on the apical margin of the clypeus (four times as long as diameter of median ocellus) (Fig. 6H). Females are difficult to distinguish from M. lippiae, which has suberect pale setae and erect black setae on T6 and a short medial carina on the apical margin of the clypeus (two times as long as diameter of median ocellus) (Fig. 6G). For further details on identification issues see Taxonomic Challenges. The male of M. coquilletti can be distinguished by its narrow probasitarsus (Fig. 8A), which is not excavated ventrally, and light to dark yellow coloration on tarsomeres 2–4.</p><p>Notes. This species has been collected in central and western Montana (Fig. 1H). Photographs, illustrations, full morphological descriptions, and notes on the biology of this species can be found in Sheffield et al. (2011) and Bzdyk (2012).</p></div>	https://treatment.plazi.org/id/03C17C29FFF5FF8673BD7C4D91387031	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF5FF8673BD7FD0949277DD.text	03C17C29FFF5FF8673BD7FD0949277DD.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachile) centuncularis (Linnaeus 1758)	<div><p>Megachile (Megachile) centuncularis (Linnaeus, 1758)</p><p>Apis centuncularis Linnaeus, 1758: 575 .</p><p>Megachile (Athemois) centuncularis; Mitchell 1935b.</p><p>Megachile (Megachile) centuncularis; Mitchell 1962: 124; 1980: 25. Butler 1965: 5. Hurd 1979: 2055. Ivanochko 1979: 145. Gonzalez 2008: 35. Scott et al. 2011: 55. Sheffield et al. 2011: 44. Sheffield and Heron 2019: 70.</p><p>Diagnosis. The female of M. centuncularis can be identified by its 5-toothed mandibles with evenly deep emarginations between all teeth (Fig. 7G), black setae on T6, and yellow to orange scopal setae on S2–6. It is most similar to M. relativa, which has golden setae on T6. The male of M. centuncularis can be identified by its narrow brown to black probasitarsi (Fig. 8A), sparse setae on T6, absence of a procoxal spine, and absence of a median tubercle on the clypeus. The male of M. centucularis is most similar to M. lapponica / M. relativa, which has a small triangular median tubercle on the clypeal margin.</p><p>Notes. This species is a new state record for Montana, though it is widespread elsewhere in North America. In Montana, it has been sparsely collected in a few western localities (Fig. 1G). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFF5FF8673BD7FD0949277DD	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF5FF8673BD7AE194327295.text	03C17C29FFF5FF8673BD7AE194327295.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) dakotensis Mitchell 1926	<div><p>Megachile (Megachiloides) dakotensis Mitchell, 1926</p><p>Megachile dakotensis Mitchell, 1926b: 164 .</p><p>Megachile (Xeromegachile) dakotensis; Mitchell 1937a: 335; 1944: 136; 1962: 145. Hurd 1979: 2063.</p><p>Megachile (Megachiloides) dakotensis; Raw 2002: 17.</p><p>Diagnosis. The female of M. dakotensis can be identified by the shape of T3–5, which are strongly concave between the depressed apical and basal grooves (Fig. 7O), reddish tibiae apically, and the asymmetrical emargination between its 3 rd and 4 th (basal) teeth with emargination deepest closer to the 4 th tooth (Fig. 7C). The male of M. dakotensis can be identified by its procoxal spine (Fig. 8H), which is longer than wide, reddish tibiae apically (front tibiae can be yellowish apically), and the shape of T2–4, which are strongly concave between the depressed apical and basal grooves (Fig. 10D).</p><p>Notes. Mitchell (1937a) recorded this species from Montana without a more specific locality, and since then, only two specimens have been collected in Montana, both at Medicine Rocks State Park, near the eastern border, in 2020 (Fig. 1I). We have been unable to locate Michell’s voucher. This rarely collected species was first described in Mitchell 1926b, then redescribed in Mitchell (1937a) and Mitchell (1962) with male characters illustrated. Photographs of both sexes can be found on BOLD (http://www.barcodinglife.org).</p></div>	https://treatment.plazi.org/id/03C17C29FFF5FF8673BD7AE194327295	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF4FF8773BD7C7493F0701D.text	03C17C29FFF4FF8773BD7C7493F0701D.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Sayapis) fidelis Cresson 1878	<div><p>Megachile (Sayapis) fidelis Cresson, 1878</p><p>Megachile fidelis Cresson, 1878: 120 . Drons 2012: 58.</p><p>Megachile (Sayapis) fidelis; Mitchell 1937c: 180. Butler 1965: 12. Hurd 1979: 2070. Ivanochko 1979: 325. Scott et al. 2011: 56. Sheffield et al. 2011: 64. Kuhlman and Burrows 2017: 13. Reese et al. 2018: 22. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Diagnosis. The female of M. fidelis is distinguished by its subparallel metasoma (viewed dorsally) (Fig. 6C) and clypeal margin with two prominent, wide, lateral tubercles surrounding a median triangular tubercle (Fig. 6F), which is unique among documented Montana Megachile species. The male of M. fidelis is distinguished by its thin and narrowly pointed procoxal spine (Fig. 8H) and its widely expanded and ventrally excavated probasitarsus (Fig. 8B) with dark setae along the entire posterior edge of the scoop-shaped dilation. The male of M. fidelis is most similar to M. pugnata, which has dark setae along only the basal ⅓ of the posterior edge of the scoop-shaped dilation.</p><p>Notes. This species has been recorded mainly in western Montana (Fig. 1K), with one record further east in Musselshell County, but it would be expected to be found in the eastern half of the state due to a record of M. fidelis from the Black Hills of South Dakota (Drons 2012). Photographs, a full morphological description, and notes on the biology of this cavity-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFF4FF8773BD7C7493F0701D	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF4FF8773BD7FD090E97787.text	03C17C29FFF4FF8773BD7FD090E97787.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Xanthosarus) dentitarsus Sladen 1919	<div><p>Megachile (Xanthosarus) dentitarsus Sladen, 1919</p><p>Megachile dentitarsus Sladen, 1919: 85 . Drons 2012: 58. Adhikari et al. 2019: Supplementary Table S4.</p><p>Megachile (Xanthosarus) dentitarsus; Mitchell 1936: 127. Butler 1965: 11. Hurd 1979: 2067. Scott et al. 2011: 56. Sheffield et al. 2011: 73.</p><p>Diagnosis. The female of M. dentitarsus can be identified by its consistently wide, white apical setal bands on T3–5 and its 5-toothed mandibles (Fig. 7F), with the deepest emargination between the 3 rd and 4 th tooth, strongly angled towards the 4 th tooth. Females are most commonly confused with M. latimanus / M. perihirta females, which have medially incomplete apical setal bands. The male of M. dentitarsus can be identified by its widely expanded and ventrally excavated probasitarsus (Fig. 8B), the smooth, glabrous ventral protuberance on its mesobasitarsus (Fig. 8D), and the small spine on the ventral mesepisternum (viewed ventrally, directly anterior to mesocoxa). Males are most similar to M. perihirta, in which the ventral mesepisternum (viewed ventrally, directly anterior to mesocoxa) has a smooth, spineless carina instead of a spine.</p><p>Notes. In Montana, this species is widespread east of the continental divide (Fig. 1J). Photographs, a full morphological description, and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFF4FF8773BD7FD090E97787	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFF4FFB873BD7A8D94D17478.text	03C17C29FFF4FFB873BD7A8D94D17478.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Xanthosarus) frigida Smith 1853	<div><p>Megachile (Xanthosarus) frigida Smith, 1853</p><p>Megachile frigida Smith, 1853: 193 . Drons 2012: 58.</p><p>Megachile (Delomegachile) frigida; Mitchell 1942: 116; 1944: 135; 1962: 133. Butler 1965: 6. Hurd 1979: 2059. Ivanochko 1979: 195.</p><p>Megachile (Xanthosarus) frigida; Scott et al. 2011: 56. Sheffield et al. 2011: 76. Reese et al. 2018: 22. Delphia et al. 2019a: 25. Delphia et al. 2019b: 649. Sheffield and Heron 2019: 70.</p><p>Megachile (Delomegachile) frigida appalachensis Mitchell, 1962: 134 .</p><p>Megachile (Delomegachile) vidua var. appalachensis Mitchell, 1935b: 205 .</p><p>Megachile vidua, not Smith, 1853 (misidentification); Fultz 2005: 134.</p><p>Diagnosis. The female of M. frigida can be identified by its 4-toothed mandibles with a truncate basal mandibular tooth (Fig. 7E), dark brown to black setae on T6, and mostly yellow to orange scopal setae on S6. The female of M. frigida is most similar to M. latimanus / M. perihirta, which has 5-toothed mandibles (Fig. 7F) and orange setae on T6. The male of M. frigida can be identified by its widely expanded and ventrally excavated probasitarsus (Fig. 8B) and two brown stripes on the ventral profemur, which is unique among male Megachile documented in Montana.</p><p>Notes. This widespread, distinctive species is found across Montana, though it has been sparsely collected in the eastern half of the state (Fig. 1L). It is known to nest in rotting logs, cavities, and bark mulch (Sheffield et al. 2011; Delphia et al. 2019b). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011). The voucher for the misidentified specimen (Fultz 2005) is in the MTEC identified as a male M. frigida (MTEC 088592) (Table 2; Supp. Material 2: Erroneous Records).</p></div>	https://treatment.plazi.org/id/03C17C29FFF4FFB873BD7A8D94D17478	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCBFFB873BD7BC891F9739B.text	03C17C29FFCBFFB873BD7BC891F9739B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) gentilis Cresson 1872	<div><p>Megachile (Litomegachile) gentilis Cresson, 1872</p><p>Megachile gentilis Cresson, 1872: 267 .</p><p>Megachile (Litomegachile) gentilis; Mitchell 1935a: 23. Butler 1965: 3. Hurd 1979: 2053. Gonzalez 2008: 35. Sheffield et al. 2011: 36. Bzdyk 2012: 44. Sheffield and Heron 2019: 70.</p><p>Diagnosis. The female of M. gentilis can be identified by the black scopal setae on S6, white scopal setae on S2–5, and 4-toothed mandibles with an angulate basal mandibular tooth appearing as a weak additional tooth (i.e., 5- toothed) (Fig. 7D). The female of M. gentilis is closest to M. mendica, which has mostly yellow to light orange scopal setae on S6 but can approach ca. 50% black scopal setae apically. For further details on identification issues see Taxonomic Challenges. The male of M. gentilis can be identified by its narrow probasitarsus, which is not excavated ventrally, T5 without a white apical setal band (may have some setae laterally), and T4–5 dull with punctures ca. 1 diameter apart. The male of M. gentilis is closest to M. mendica, in which T4–5 is polished and shiny, with punctures 2–4 diameters apart.</p><p>Notes. This species is a new state record for Montana and has been collected from scattered localities in central and western Montana (Fig. 1N). Megachile gentilis nests in natural cavities as well as trap nests (Sheffield et al. 2011). Photographs, illustrations, full morphological descriptions, and notes on its biology can be found in Sheffield et al. (2011) and Bzdyk (2012).</p></div>	https://treatment.plazi.org/id/03C17C29FFCBFFB873BD7BC891F9739B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCBFFB873BD7E299195715B.text	03C17C29FFCBFFB873BD7E299195715B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Xanthosarus) gemula Cresson 1878	<div><p>Megachile (Xanthosarus) gemula Cresson, 1878</p><p>Megachile gemula Cresson, 1878: 118 . Mitchell 1927b: 178. Drons 2012: 58.</p><p>Megachile (Delomegachile) gemula Cresson; Mitchell 1935b: 181; 1936: 185; 1962: 134. Butler 1965: 6. Hurd 1979: 2059. Ivanochko 1979: 186.</p><p>Megachile (Xanthosarus) gemula; Raw 2002: 36. Scott et al. 2011: 56. Sheffield et al. 2011: 78. Reese et al. 2018: 23. Delphia et al. 2019b: 649. Sheffield and Heron 2019: 70.</p><p>Diagnosis. The female of M. gemula can be identified by white pubescence on T1–2 that contrasts with the dark pubescence on T3–5, reddish-brown to black scopal setae on S2–6, 4-toothed mandibles with a truncate basal tooth (Fig. 7E), and base of mandibles square-shaped (viewed laterally) with parallel sides for a distance as long as wide, then tapering apically (Fig. 6J). Females of M. gemula are most similar to M. melanophaea, which have mandibles gradually tapering in width towards apex (from a lateral view) (Fig. 6I) and orange scopal setae on S2–6. The male of M. gemula can be identified by its narrow, ventrally excavated probasitarsus, 4-toothed mandibles, and acute posterior angle of the dorsal face of the protibia, the apex entirely dark. The male of M. gemula is most similar to M. melanophaea, in which the dorsal face of the protibia has a rounded and spatulate posterior angle that is entirely cream to pale yellow at the apex.</p><p>Notes. Megachile gemula is found widely in Montana though, like many species, has not been extensively collected in eastern regions of the state (Fig. 1M). It is known to nest in poplar logs and hollow twigs (Sheffield et al. 2011). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCBFFB873BD7E299195715B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCBFFB973BD780594BF74B4.text	03C17C29FFCBFFB973BD780594BF74B4.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachile) inermis Provancher 1888	<div><p>Megachile (Megachile) inermis Provancher, 1888</p><p>Megachile inermis Provancher, 1888: 323 . Drons 2012: 58.</p><p>Megachile (Anthemois) inermis; Mitchell 1935b: 171.</p><p>Megachile (Megachile) inermis; Mitchell 1962: 126. Hurd 1979: 2055. Ivanochko 1979: 133. Scott et al. 2011: 55. Sheffield et al. 2011: 45. Sheffield and Heron 2019: 70.</p><p>Diagnosis. The female of M. inermis can be identified by its distinctively large body size (17–20 mm long), shiny clypeus with sparse punctation medially (punctures 1–3 diameters apart), and clypeal margin with four prominent tubercles. The male of M. inermis can be identified by its large body size (11–16 mm long), unevenly spaced 3- toothed mandibles (2 nd tooth closer to apical tooth), and its nub-like procoxal spine, which is wider than long and covered with a small tuft of dense orange setae. Males are most similar to M. montivaga, which has evenly spaced teeth.</p><p>Notes. Megachile inermis, a distinctively large species, has been recorded in several localities in western Montana (Fig. 1O). This species is known to nest in cavities and rotting logs (Sheffield et al. 2011). Photographs, a full morphological description, and notes on its biology can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCBFFB973BD780594BF74B4	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCAFFB973BD7D659302704F.text	03C17C29FFCAFFB973BD7D659302704F.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachile) lapponica Thomson 1872	<div><p>Megachile (Megachile) lapponica Thomson, 1872</p><p>Megachile lapponica Thomson, 1872: 227 .</p><p>Megachile (Megachile) lapponica; Sheffield et al. 2011: 47. Kuhlman and Burrows 2017: 13. Reese et al. 2018: 22. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 70.</p><p>Megachile nivalis Friese, 1903: 246 .</p><p>Megachile (Anthemois) santiamensis Mitchell, 1934: 311 .</p><p>Megachile (Anthemois) nivalis; Mitchell 1935b: 174; 1942: 115.</p><p>Megachile (Megachile) nivalis; Mitchell 1962: 129. Hurd 1979: 2056. Ivanochko 1979: 170. Sheffield and Westby 2007: 178. Scott et al. 2011: 55.</p><p>Diagnosis. The females of M. lapponica can be identified by their5-toothed mandibles with evenly deep emarginations between teeth (Fig. 7G), brown to black scopal setae on S6, and scopal setae on S5 black apically and yellow to pale orange basally. The female of M. lapponica is most similar to M. relativa, which has golden scopal setae on S6, and M. centuncularis, which has black setae on T6. The males of M. lapponica cannot be reliably separated from males of M. relativa in Montana based on external morphology or by examining the genitalia (see Taxonomic Challenges; Sheffield &amp; Westby 2007). Males of M. lapponica / M. relativa can be recognized by the absence of a procoxal spine, small median triangular tubercle on the clypeal margin, narrow brown to black probasitarsi, evenly spaced 3-dentate mandibles, and T6 with sparse setae, not tomentose. Megachile lapponica / M. relativa is most similar to M. centuncularis (see M. centuncularis above).</p><p>Notes. Megachile lapponica females have been found in scattered localities across the western half of Montana (Fig. 1P). Photographs, a full morphological description (but see Taxonomic Challenges), and notes on the biology of M. lapponica can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCAFFB973BD7D659302704F	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCAFFBA73BD7A3C932B75B0.text	03C17C29FFCAFFBA73BD7A3C932B75B0.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Xanthosarus) latimanus Say 1823	<div><p>Megachile (Xanthosarus) latimanus Say, 1823</p><p>Megachile latimanus Say, 1823: 81 .</p><p>Megachile (Xanthosarus) latimanus; Mitchell 1936: 130; 1962: 157. Hurd 1979: 2067. Ivanochko 1979: 268. Fultz 2005: 134. Scott et al. 2011: 56. Sheffield et al. 2011: 79. Reese et al. 2018: 23. Delphia et al. 2019a: 25. Engel 2020: 11.</p><p>Megachile (Delomegachile) vidua Smith, 1853: 192 . Mitchell 1935b: 200.</p><p>Megachile latimanus / perihirta; Pearce 2008: 57.</p><p>Diagnosis. The females of M. latimanus cannot be reliably separated from M. perihirta in Montana based on morphology (see Taxonomic Challenges). Megachile latimanus / M. perihirta have 5-toothed mandibles with the deepest emargination between the 3 rd and 4 th teeth, emargination strongly angled towards the 4 th tooth (Fig. 7F), and medially incomplete apical setal bands on T3–5. Females are most similar to M. dentitarsus, which has T3–5 apical setal bands consistently wide, as wide medially as laterally. The male of M. latimanus can be identified by its widely expanded and ventrally excavated probasitarsus (Fig. 8B), the wide, rounded, ventral protuberance of the mesobasitarsus basally (viewed anteriorly) (Fig. 8C), and the widely depressed ventral side of the mesofemur. Males are most similar to M. perihirta, which has mesobasitarsus with narrowly rounded, ventral protuberance basally (Fig. 8D) and the smooth, convexly rounded ventral side of mesofemur.</p><p>Notes. Megachile latimanus has been recorded in a few scattered localities across Montana (Fig. 1Q). Photographs, a full morphological description (but see Taxonomic Challenges), and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCAFFBA73BD7A3C932B75B0	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC9FFBA73BD7E619105715C.text	03C17C29FFC9FFBA73BD7E619105715C.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) lippiae Cockerell 1900	<div><p>Megachile (Litomegachile) lippiae Cockerell, 1900</p><p>Megachile cleomis var. lippiae Cockerell, 1900: 15 .</p><p>Megachile texana var. lippiae Cockerell, 1900: 223 . Mitchell 1935a: 37.</p><p>Megachile lippiae; Pearce 2008: 51. Pearce et al. 2012: 101.</p><p>Megachile (Litomegachile) lippiae; Butler 1965: 3. Hurd 1979: 2053. Scott et al. 2011: 55. Sheffield et al. 2011: 38. Bzdyk 2012: 46. Kuhlman and Burrows 2017: 12. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Megachile concinna, not Smith, 1879 (misidentification); Pearce 2008: 107.</p><p>Diagnosis. The female of M. lippiae can be identified by its suberect white setae and erect black setae on T6 and apically concave T6 (viewed laterally) (Fig. 7N). The female is difficult to discern from M. coquilletti (see M. coquilletti above) (see Taxonomic Challenges). The male of M. lippiae can be identified by its narrow probasitarsus, which is not excavated ventrally, the apical margin of T6 (ventrad to the transverse carina) with submedian teeth closer to lateral teeth than to each other (Fig. 9F), the scutum with less than 25% black pubescence, and mostly white pubescence on the dorsal tergites and vertex of head. The male of M. lippiae is most similar to M. texana, which has greater than 50% black pubescence on the scutum, tergites with significant bands of black pubescence, and the vertex of head with greater than 50% black pubescence (see Taxonomic Challenges).</p><p>Notes. Megachile lippiae has been collected widely across Montana (Fig. 1R). Photographs, illustrations, full morphological descriptions, and notes on the biology of this species can be found in Sheffield et al. (2011) and Bzdyk (2012). Sheffield and Genaro (2013) briefly made a claim of validity for Megachile cleomis Cockerell. See Taxonomic Challenges above for a discussion of this issue. The voucher for the misidentified specimen (Pearce 2008) is in the MTEC identified as a male M. lippiae (MTEC 088326) (Table 2; Supp. Material 2: Erroneous Records).</p></div>	https://treatment.plazi.org/id/03C17C29FFC9FFBA73BD7E619105715C	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC9FFBA73BD7BCD92A0739B.text	03C17C29FFC9FFBA73BD7BCD92A0739B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) manifesta Cresson 1878	<div><p>Megachile (Megachiloides) manifesta Cresson, 1878</p><p>Megachile manifesta Cresson, 1878: 122 . Drons 2012: 58.</p><p>Megachile (Xeromegachile) manifesta; Mitchell 1937a: 352. Butler 1965: 8. Hurd 1979: 2064.</p><p>Megachile (Megachiloides) manifesta; Raw 2002: 18. Scott et al. 2011: 55. Sheffield et al. 2011: 55.</p><p>Diagnosis. The female of M. manifesta can be identified by its 4-toothed mandibles with an asymmetrical emargination between the 3 rd and 4 th teeth that is deepest nearer the 4 th tooth (Fig. 7C), black scopal setae on S6 and at least the apical part of S5, the basal portion with white scopal setae, and T5 surface matte to shiny with punctures ≤ 1 diameter apart medially. Females are closest to M. nevadensis, which has all white scopal setae on S5, and M. wheeleri, which has the surface of T5polished and shiny with punctures 2–4 diameters apart medially (see Taxonomic Challenges). The male of M. manifesta can be identified by its wide and spatulate procoxal spine without a setae patch at the base (Fig. 8I), triangular metatarsomeres (viewed laterally) (Fig. 8F), and a smooth, rounded carina on the ventral mesepisternum (viewed ventrally, directly posterior to the procoxal spine). The male of M. manifesta is most similar to M. wheeleri, which differs in having quadrate metatarsomeres (viewed laterally) (Fig. 8G).</p><p>Notes. This species, in general occurring in the western U.S. and Canada, is found in drier areas of eastern and south-central Montana (Fig. 1S). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFC9FFBA73BD7BCD92A0739B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC9FFBB73BD7808910D771D.text	03C17C29FFC9FFBB73BD7808910D771D.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Xanthosarus) melanophaea Smith 1853	<div><p>Megachile (Xanthosarus) melanophaea Smith, 1853</p><p>Megachile melanophaea Smith, 1853: 191 . Drons 2012: 58. Burkle et al. 2020: 7.</p><p>Megachile (Delomegachile) melanophaea; Mitchell 1935b: 190; 1962: 138. Butler 1965: 6. Hurd 1979: 2060. Ivanochko 1979: 215. Fultz 2005: 134.</p><p>Megachile (Xanthosarus) melanophaea; Scott et al. 2011: 56. Sheffield et al. 2011: 81. Kuhlman and Burrows 2017: 13. Reese et al. 2018: 23. Delphia et al. 2019a: 25. Sheffield and Heron 2019: 70.</p><p>Megachile melanophaea wootoni; Mitchell 1935b: 190.</p><p>Diagnosis. The female of M. melanophaea can be distinguished by its white pubescence on T1–2, contrasting the dark pubescence on T3–5, orange scopal setae on S2–6, and mandibles gradually tapering in width from base to apex (viewed laterally) (Fig. 6I). The female of M. melanophaea is most similar to M. gemula (see M. gemula above). The male of M. melanophaea can be identified by its 4-toothed mandibles and the dorsal face of the protibia, which has a rounded, spatulate posterior angle and an entirely pale apex. The male of M. melanophaea is most similar to M. gemula (see M. gemula above).</p><p>Notes. This species has been collected widely in Montana, with sparser records in the eastern part of the state, reflecting the general trend of more intensive collecting in the western portion of the state (Fig. 1T). Photographs, a full morphological description, and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFC9FFBB73BD7808910D771D	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC8FFBB73BD7A2193CB72D5.text	03C17C29FFC8FFBB73BD7A2193CB72D5.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) mendica Cresson 1878	<div><p>Megachile (Litomegachile) mendica Cresson, 1878</p><p>Megachile mendica Cresson, 1878: 126 . Drons 2012: 58.</p><p>Megachile (Litomegachile) mendica; Mitchell 1935a: 26; 1962: 117. Butler 1965: 3. Hurd 1979: 2053. Ivanochko 1979: 96. Scott et al. 2011: 55. Sheffield et al. 2011: 39. Bzdyk 2012: 47. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Diagnosis. The female of M. mendica is distinguished by its mostly yellow to orange scopal setae on S5 and S6, with only a few black scopal setae, T6 straight (viewed laterally) (Fig. 7J) with brown appressed setae, and 4-toothed mandibles with an angulate basal tooth, appearing as a weak additional tooth (i.e., 5-toothed) (Fig. 7D). Females of M. mendica are most similar to M. gentilis (see M. gentilis above), and M. snowi, which has white appressed setae on T6 ( M. snowi is a prior subspecies of M. mendica; Byzdk 2012). The male of M. mendica is distinguished by its narrow probasitarsus, which is not excavated ventrally (Fig. 8A), T5 without a white apical setal band, and T4–5 polished and shiny with punctures 2–4 diameters apart. The male of M. mendica is most similar to M. gentilis (see M. gentilis above) and M. snowi, which differs in having a complete T5 white apical setal band.</p><p>Notes. This species is a new state record for Montana and has only been collected from two localities in eastern Montana (Fig. 1V). Photographs, illustrations, full morphological descriptions, and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011) and Bzdyk (2012).</p></div>	https://treatment.plazi.org/id/03C17C29FFC8FFBB73BD7A2193CB72D5	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC8FFBB73BD7D8D91957071.text	03C17C29FFC8FFBB73BD7D8D91957071.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Sayapis) mellitarsis Cresson 1878	<div><p>Megachile (Sayapis) mellitarsis Cresson, 1878</p><p>Megachile mellitarsis Cresson, 1878: 121 .</p><p>Megachile (Sayapis) mellitarsis; Mitchell 1937c: 194. Hurd 1979: 2071. Ivanochko 1979: 328. Scott et al. 2011: 56. Sheffield et al. 2011: 66. Sheffield and Heron 2019: 70.</p><p>Diagnosis. The female of M. mellitarsis can be distinguished by the two broadly incurved emarginations on its clypeal margin (Fig. 6E), 4-toothed mandibles with evenly deep emarginations between all teeth, and reddish-brown tarsi contrasting the black tibia on the legs. The male of M. mellitarsis can be distinguished by the thin, narrowly pointed procoxal spine (Fig. 8H), orangish brown meso- and metatarsi, and the distinctly yellow protarsi with elongated apical dilation that reaches apex of the 3 rd tarsomere. The male of M. mellitarsis is closest to M. pugnata and M. fidelis, both of which have front basitarsi with apical dilation not reaching 3 rd tarsomere. For more details on identification issues see Taxonomic Challenges.</p><p>Notes. This species is a new state record for Montana. Other than a record from British Columbia’s Western Interior Basin (Sheffield 2019), this dry-land species is at the northern edge of its known range in southern Montana (Fig. 1U). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFC8FFBB73BD7D8D91957071	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCFFFBD73BD794B937675B0.text	03C17C29FFCFFFBD73BD794B937675B0.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) onobrychidis Cockerell 1908	<div><p>Megachile (Litomegachile) onobrychidis Cockerell, 1908</p><p>Megachile onobrychidis Cockerell, 1908: 266 .</p><p>Megachile (Litomegachile) brevis onobrychidis; Butler 1965: 2. Hurd 1979: 2052. Scott et al. 2011: 55.</p><p>Megachile (Litomegachile) onobrychidis; Ivanochko 1979: 90. Sheffield et al. 2011: 41. Bzdyk 2012: 50. Kuhlman and Burrows 2017: 12. Reese et al. 2018: 22. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Diagnosis. The female of M. onobrychidis can be identified by the shape of T6, which is strongly convex basally and concave apically (Fig. 7K), black setae on T6, 4-toothed mandibles with an even semicircular emargination between the 3 rd and 4 th teeth (Fig. 7B), and black scopal setae on S6. The females are most similar to M. brevis (see M. brevis above). The male of M. onobrychidis can be identified by the sparse setae on T6, the shape of the procoxal spine, which is longer than wide, and the shorter ocelloccipital distance compared to the ocellocular distance (Fig. 8L).</p><p>Notes. Megachile onobrychidis is found across Montana, though like many other species, has been less collected in eastern parts of the state (Fig. 1Y). Photographs, illustrations, full morphological descriptions, and notes on its biology can be found in Sheffield et al. (2011) and Bzdyk (2012).</p></div>	https://treatment.plazi.org/id/03C17C29FFCFFFBD73BD794B937675B0	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCFFFBC73BD7FD092A477B2.text	03C17C29FFCFFFBC73BD7FD092A477B2.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachile) montivaga Cresson 1878	<div><p>Megachile (Megachile) montivaga Cresson, 1878</p><p>Megachile montivaga Cresson, 1878: 124 . Drons 2012: 58.</p><p>Megachile (Anthemois) montivaga; Mitchell 1935b: 167.</p><p>Megachile (Megachile) montivaga; Mitchell 1962: 127. Butler 1965: 5. Hurd 1979: 2056. Ivanochko 1979: 127. Gonzalez 2008: 35. Scott et al. 2011: 55. Sheffield et al. 2011: 49. Kuhlman and Burrows 2017: 13. Reese et al. 2018: 22. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Diagnosis. The female of M. montivaga is distinguished by its light yellow to orange scopal setae on S2–S6, appressed cream-colored setae on T6, its 5-toothed mandibles, which have no cutting edge ventrad the tooth plane, and an elevated ridge running dorsally from the apex of the 2 nd tooth to the point of attachment of the mandible (Fig. 7H). The male of M. montivaga is distinguished by its three evenly spaced mandibular teeth and its nub-like procoxal spine, which is wider than long and covered with a small tuft of dense orange setae. The male of M. montivaga is most similar to M. inermis (see M. inermis above).</p><p>Notes. Megachile montivaga has been widely collected in western Montana and from a few eastern localities (Fig. 1W). It is known to nest in soil and old stems. Photographs, a full morphological description, and notes on its biology can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCFFFBC73BD7FD092A477B2	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCFFFBC73BD7C6F93A170DE.text	03C17C29FFCFFFBC73BD7C6F93A170DE.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) nevadensis Cresson 1879	<div><p>Megachile (Megachiloides) nevadensis Cresson, 1879</p><p>Megachile nevadensis Cresson, 1879: 209 .</p><p>Megachile (Xeromegachile) nevadensis; Mitchell 1937a: 359. Hurd 1979: 2064.</p><p>Megachile (Megachiloides) nevadensis; Raw 2002: 19. Scott et al. 2011: 56.</p><p>Diagnosis. The female of M. nevadensis can be identified by its black scopal setae on S6, white scopal setae on S5, T5 with punctures ≤ 1 diameter apart medially, and 4-toothed mandibles with an asymmetrical emargination between the 3 rd and 4 th teeth that is deepest nearer the 4 th tooth (Fig. 7C). The females are most similar to M. manifesta (see M. manifesta above) and M. wheeleri, which has T5 with punctures 2–4 diameters apart medially (see Taxonomic Challenges). The male of M. nevadensis can be identified by its 3-toothed mandibles, its wide and spatulate procoxal spine (Fig. 8I), with a short, suberect patch of setae at the base, and carina on mesepisternum with long setae touching the hind coxae. The males are most similar to M. wheeleri and M. manifesta, neither of which have a patch of setae at the base of the procoxal spine.</p><p>Notes. This species was recorded from Bozeman, Montana, by Mitchell (1937a), but we were unable to locate the voucher (see Discussion: Searching for Mitchell’s Montana Species). However, collecting in eastern Montana resulted in collection of one male specimen of M. nevadensis in 2021 (Fig. 1X). The species was first described in Cresson (1879), then redescribed in more detail in Mitchell (1937a) with illustrations of male characters. Photographs of both sexes can be found on BOLD (http://www.barcodinglife.org).</p></div>	https://treatment.plazi.org/id/03C17C29FFCFFFBC73BD7C6F93A170DE	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCEFFBD73BD7E61951C767C.text	03C17C29FFCEFFBD73BD7E61951C767C.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Argyropile) parallela Smith 1853	<div><p>Megachile (Argyropile) parallela Smith, 1853</p><p>Megachile parallela Smith, 1853: 191 . Pearce 2008: 51. Drons 2012: 58. Pearce et al. 2012: 101.</p><p>Megachile (Argyropile) parallela; Mitchell 1937b: 48. Mitchell 1943: 12; 1944: 132; 1962: 159. Butler 1965: 10. Hurd 1979: 2066. Ivanochko 1979: 303. Gonzalez and Griswold 2007: 3. Gonzalez 2008: 161. Scott et al. 2011: 54. Sheffield et al. 2011: 23. Kuhlman and Burrows 2017: 12. Reese et al. 2018: 21. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 69. Engel 2020: 10.</p><p>Megachile (Argyropile) asterae Mitchell, 1943: 13 .</p><p>Diagnosis. The female of M. parallela can be identified by the upcurve at the apical end of S6, which extends past T6 (Fig. 7L) and the appressed white to yellow setae on T6. The male of M. parallela can be identified by the two pairs of prominent teeth on the apical margin of T6, (Fig. 9C) and large, semi-circular emargination of the pre-apical carina of T6.</p><p>Notes. This species is recorded from localities across Montana (Fig. 1Z). Photographs, a full morphological description, and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCEFFBD73BD7E61951C767C	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCEFFBD73BD7C2D952F7002.text	03C17C29FFCEFFBD73BD7C2D952F7002.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) pascoensis Mitchell 1934	<div><p>Megachile (Megachiloides) pascoensis Mitchell, 1934</p><p>Megachile (Xeromegachile) pascoensis Mitchell, 1934: 320 .</p><p>Megachile (Derotropis) pascoensis; Mitchell 1944: 142. Hurd 1979: 2062.</p><p>Megachile (Megachiloides) pascoensis; Raw 2002: 16. Kuhlman and Burrows 2017: 13.</p><p>Megachile gabrielensis Michell, 1934: 346; 1936: 159.</p><p>Diagnosis. The female of M. pascoensis can be identified by its 3-toothed mandibles (Fig. 7A) and pitted, dull T6 with punctures ≤ 1 diameter apart. The females are most similar to M. anograe (see M. anograe above). The male of M. pascoensis can be identified by its clypeal margin, which has a deep U-shaped median emargination (as deep as wide) (Fig. 10A) and the white apical setal band on T5.</p><p>Notes. This distinctive species is rare outside of California. In Montana, it is known from a historical record (Mitchell 1934) and two specimens from Missoula County (Kuhlman &amp; Burrows 2017) (Fig. 1 AA). The species was first described in Mitchell (1934) (male = M. pascoensis; female = M. gabrielensis) and has not been redescribed or illustrated since. Photographs of the types of both sexes can be found on Big-Bee (Seltmann et al. 2021).</p></div>	https://treatment.plazi.org/id/03C17C29FFCEFFBD73BD7C2D952F7002	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCEFFBE73BD7AFE93157400.text	03C17C29FFCEFFBE73BD7AFE93157400.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Xanthosarus) perihirta Cockerell 1898	<div><p>Megachile (Xanthosarus) perihirta Cockerell, 1898</p><p>Megachile perihirta Cockerell, 1898: 126 . Drons 2012: 58. Adhikari et al. 2019: Supplementary Table S4.</p><p>Megachile (Xanthosarus) perihirta; Mitchell 1936: 136. Butler 1965: 11. Hurd 1979: 2067. Fultz 2005: 134. Scott et al. 2011: 56. Sheffield et al. 2011: 83. Kuhlman and Burrows 2017: 13. Reese et al. 2018: 23. Delphia et al. 2019a: 25. Sheffield and Heron 2019: 70. Engel 2020: 11.</p><p>Megachile fortis, not Cresson, 1872 (misidentification); Simanonok 2018: 89.</p><p>Megachile circumcincta, not Kirby, 1802 (misidentification); Adhikari et al. 2019: Supplementary Table S4.</p><p>Diagnosis. The females of M. latimanus and M. perihirta cannot be reliably separated in Montana based on morphology (see M. perihirta above) (see Taxonomic Challenges). Megachile latimanus / M. perihirta has 5-toothed mandibles with the deepest emargination between the 3 rd and 4 th teeth, emargination strongly angled towards the 4 th tooth (Fig. 7F), and medially incomplete apical setal bands on T3–5. The male of M. perihirta can be identified by its widely expanded probasitarsus (Fig. 8B), which is excavated ventrally, narrowly rounded, ventral protuberance on its basal mesobasitarsus (viewed anteriorly) (Fig. 8D), and smooth, convexly rounded anterior mesofemur. The males are most similar to M. dentitarsu s (see M. dentitarsus above).</p><p>Notes. Megachile perihirta is a common, widespread species in Montana (Fig. 1 AB). Photographs, a full morphological description (but see Taxonomic Challenges), and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011). The vouchers for the misidentified specimens (Simanonok 2018) are in the Burkle Community Ecology Lab at Montana State University identified as female M. latimanus / M. perihirta (8713MS16, 19715EE, 20725MS16, 11617MS16, 9721EE) (Table 2; Supp. Material 2: Erroneous Records). The voucher for the misidentified specimen (Adhikari et al. 2019) is in the MTEC identified as a male M. perihirta (MTEC 035028) (Supp. Material 2: Erroneous Records).</p></div>	https://treatment.plazi.org/id/03C17C29FFCEFFBE73BD7AFE93157400	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCDFFBE73BD7B8A91EA72F2.text	03C17C29FFCDFFBE73BD7B8A91EA72F2.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachile) relativa Cresson 1878	<div><p>Megachile (Megachile) relativa Cresson, 1878</p><p>Megachile relativa Cresson, 1878: 126 . Mitchell 1927b: 179. Jensen 2003: 195. Fultz 2005: 82. Drons 2012: 59.</p><p>Megachile (Anthemois) relativa; Mitchell 1935b: 162.</p><p>Megachile (Megachile) relativa; Mitchell 1962: 129. Butler 1965: 5. Hurd 1979: 2056. Ivanochko 1979: 153. Sheffield and Westby 2007: 178. Scott et al. 2011: 55. Sheffield et al. 2011: 51. Kuhlman and Burrows 2017: 13. Reese et al. 2018: 22. Delphia et al. 2019a: 25. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Megachile aspera Mitchell, 1924: 158 .</p><p>Diagnosis. The female of M. relativa can be identified by its 5-toothed mandibles (Fig. 7G), yellow-orange scopal setae on S2–6, and golden pubescence on T6. The females are most similar to M. centuncularis (see M. centuncularis above). The males of M. relativa cannot be reliably separated from males of M. lapponica in Montana based on external morphology or by examining the genitalia (see Taxonomic Challenges; Sheffield &amp; Westby 2007). Males of M. lapponica / M. relativa can be recognized by the absence of a procoxal spine, small median triangular tubercle on the clypeal margin, narrow brown to black probasitarsi (Fig. 8A), evenly spaced 3-dentate mandibles, and T6 with sparse setae, not tomentose. Megachile lapponica / M. relativa is most similar to M. centuncularis (see M. centuncularis above).</p><p>Notes. In Montana, this species has been collected widely but with only a few eastern localities, reflecting the general lack of collecting in the region (Fig. 1 AD). Photographs, a full morphological description (but see Taxonomic Challenges), and notes on its biology can be found in Sheffield et al. (2011). This species readily accepts trap nests (Jensen et al. 2003).</p></div>	https://treatment.plazi.org/id/03C17C29FFCDFFBE73BD7B8A91EA72F2	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCDFFBE73BD7EF193CB711E.text	03C17C29FFCDFFBE73BD7EF193CB711E.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Sayapis) pugnata Say 1837	<div><p>Megachile (Sayapis) pugnata Say, 1837</p><p>Megachile pugnatus Say, 1837: 408 .</p><p>Megachile (Sayapis) pugnata; Mitchell 1937c: 201; 1962: 179. Butler 1965: 14. Hurd 1979: 2072. Ivanochko 1979: 316. Fultz 2005: 134. Gonzalez 2008: 36. Scott et al. 2011: 56. Sheffield et al. 2011: 67. Kuhlman and Burrows 2017: 13. Reese et al. 2018: 22. Delphia et al. 2019a: 25. Sheffield and Heron 2019: 70. Engel 2020: 11.</p><p>Eumegachile (Sayapis) pugnata (Say); Mitchell 1980: 51.</p><p>Megachile pugnata; Drons 2012: 58.</p><p>Megachile inimica, not Cresson, 1872 (misidentification); Pearce 2008: 51. Pearce et al. 2012: 101.</p><p>Diagnosis. The female of M. pugnata can be identified by its parallel-sided tergites (Fig. 6C), pronounced tooth on the posterior genal margin (Fig. 7P), and clypeal margin with three tubercles. The genal tooth of the female cannot be mistaken for any other Montana Megachile species. The male of M. pugnata can be identified by its thin and narrowly pointed procoxal spine (Fig. 8H) and the scoop-shaped dilation of its probasitarsus, which has dark setae along the basal ⅓ of the posterior edge. The males are most similar to M. fidelis (see M. fidelis above).</p><p>Notes. This large, distinctive species is widespread in Montana, although most records are from the west (Fig. 1 AC). The fact that records extend to the southeast border indicates it will be found more broadly with more collecting in the under-sampled eastern part of the state. Photographs, a full morphological description, and notes on the biology of this cavity-nesting species can be found in Sheffield et al. (2011), who report that it is a Helianthus specialist. The voucher for the misidentified specimen (Pearce et al. 2012) is in the MTEC identified as a male M. pugnata (MTEC 57005) (Table 2; Supp. Material 2: Erroneous Records).</p></div>	https://treatment.plazi.org/id/03C17C29FFCDFFBE73BD7EF193CB711E	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCCFFBF73BD7FD093E77687.text	03C17C29FFCCFFBF73BD7FD093E77687.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Eutricharaea) rotundata (Fabricius 1787)	<div><p>Megachile (Eutricharaea) rotundata (Fabricius, 1787)</p><p>Apis rotundata Fabricius, 1787: 303 .</p><p>Megachile rotundata; Gerber and Akre 1969: 1. Jensen 2003: 195. O’Neill and O’Neill 2003: 447; 2011: 223. O’Neill et al. 2004: 619. Pearce 2008: 51. O’Neill et al. 2010: 775. O’Neill et al. 2011: 917. Delphia and O’Neill 2012: 380. Drons 2012: 59. Pearce et al. 2012: 97. O’Neill et al. 2014. O’Neill et al. 2015: 1. Soltani et al. 2017: 827. Donahoo et al. 2021: 444.</p><p>Megachile (Eutricharaea) rotundata (Fabricius) . Mitchell 1962: 122. Ivanochko 1979: 113. Cooper 1984: 225. Gonzalez 2008: 35. Scott et al. 2011: 54. Sheffield et al. 2011: 31. Kuhlman and Burrows 2017: 12. Reese et al. 2018: 21. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 69. Engel 2020: 10.</p><p>Apis pacifica Panzer 1798: 16 .</p><p>Megachile (Eutricharaea) pacifica; Hurd 1979: 2057.</p><p>Diagnosis. The female of M. rotundata can be identified by its white apical setal bands on S2–6 (Fig. 6A), white scopal setae on at least the basal half of S5, lateral, ovate fovea on T2, and the absence of lateral, ovate fovea on T3. The females are most similar to M. apicalis (see M. apicalis above). The male of M. rotundata can be identified by its lateral, ovate fovea on T2 and the absence of lateral, ovate fovea on T3. Males of M. rotundata are most similar to M. apicalis (see M. apicalis above).</p><p>Notes. Megachile rotundata is an introduced species that is economically important for alfalfa seed production (reviewed in Pitts-Singer &amp; Cane 2011). The first specimen of M. rotundata in Montana is from 1963. Megachile rotundata has now been recorded statewide in Montana (Fig. 1 AE). It is the only Megachile species that has legal standing in Montana, as the subject of the “Alfalfa Leaf-Cutting Bee Management Act” (2021 Montana Code Annotated Title 80. Agriculture Chapter 6. Apiculture Part 11. Alfalfa Leaf-Cutting Bees). Megachile rotundata are known to nest in a variety of substrates, including cavities, trap nests, and holes in vertical banks (see Discussion: Notes on Megachile (Eutricharaea) rotundata and Introduced Megachile Species).Photographs, a full morphological description, and notes on its biology can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCCFFBF73BD7FD093E77687	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCCFFBF73BD7B7490E8731B.text	03C17C29FFCCFFBF73BD7B7490E8731B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) snowi Mitchell 1927	<div><p>Megachile (Litomegachile) snowi Mitchell, 1927</p><p>Megachile mendica snowi Mitchell, 1927: 113 .</p><p>Megachile (Litomegachile) mendica snowi; Mitchell 1935a: 31. Butler 1965: 4. Scott et al. 2011: 55.</p><p>Megachile (Litomegachile) snowi; Bzdyk 2012: 55. Sheffield and Heron 2019: 70.</p><p>Diagnosis. The female of M. snowi can be identified by its mostly yellow to orange scopal setae on S6, white to golden appressed setae on T6, T6 straight (viewed laterally) (Fig. 7J), and 4-toothed mandibles with an angulate basal mandibular tooth, appearing as a weak additional tooth (i.e., 5-toothed) (Fig. 7D). The female of M. snowi is most similar to M. mendica (see M. mendica above). The male of M. snowi can be identified by its white apical setal band on T5 and by the apical margin of T6 (ventrad the transverse carina), which has submedian teeth that are either closer to each other than to the lateral teeth or all teeth are subequal to each other (Fig. 9E). Males of M. snowi are most similar to M. mendica (see M. mendica above).</p><p>Notes. This species is a new state record for Montana. Megachile snowi, a now-recognized species previously recognized as a subspecies of M. mendica, has only been collected from one locality in eastern Montana, a northern extension of its known range (Fig. 1 AF). Illustrations and a full morphological description can be found in Bzdyk (2012).</p></div>	https://treatment.plazi.org/id/03C17C29FFCCFFBF73BD7B7490E8731B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFCCFFB073BD7988938074B4.text	03C17C29FFCCFFB073BD7988938074B4.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) subnigra Cresson 1879	<div><p>Megachile (Megachiloides) subnigra Cresson, 1879</p><p>Megachile subnigra Cresson, 1879: 208 .</p><p>Megachile (Xeromegachile) subnigra; Mitchell 1937a: 364; 1944: 138. Hurd 1979: 2065. Ivanochko 1979: 252.</p><p>Megachile (Megachiloides) subnigra; Raw 2002: 21. Scott et al. 2011: 56. Sheffield et al. 2011. Reese et al. 2018: 22. Delphia et al. 2019a: 25. Sheffield and Heron 2019: 70.</p><p>Megachile (Xeromegachile) angelica Mitchell, 1934: 318 .</p><p>Megachile (Xeromegachile) blaisdelli Mitchell, 1934: 336 .</p><p>Megachile (Xeromegachile) moschata Mitchell, 1934: 338 .</p><p>Diagnosis. The female of M. subnigra can be identified by its all-black scopal setae on S2–6 and 4-toothed mandibles with a pointed basal mandibular tooth (Fig. 7B). The female of M. subnigra is most similar to M. gemula, which has reddish-brown scopal setae on S2–6 and a truncate basal mandibular tooth (Fig. 7E). For further details on identification issues see Taxonomic Challenges. The male of M. subnigra can be identified by the mostly black pubescence on the mid and hind legs, cream to yellow colored protarsi, and the wide, spatulate procoxal spine (Fig. 8I) with a short suberect patch of setae at the base.</p><p>Notes. Megachile subnigra is known from the southern half of central Montana, in the upper Yellowstone and upper Missouri drainages (Fig. 1 AG). Photographs, a full morphological description, and notes on the biology of this ground-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFCCFFB073BD7988938074B4	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC3FFB073BD7D65951171E3.text	03C17C29FFC3FFB073BD7D65951171E3.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Litomegachile) texana Cresson 1878	<div><p>Megachile (Litomegachile) texana Cresson, 1878</p><p>Megachile texana Cresson, 1878: 125 . Drons 2012: 59.</p><p>Megachile (Litomegachile) texana; Mitchell 1935a: 32; 1962: 118. Butler 1965: 4. Hurd 1979: 2054. Ivanochko 1979: 103. Scott et al. 2011: 55. Sheffield et al. 2011: 42. Bzdyk 2012: 56. Reese et al. 2018: 22. Sheffield and Heron 2019: 70. Engel 2020: 10.</p><p>Megachile texana var. cleomis; Mitchell 1935a: 32.</p><p>Diagnosis. The female of M. texana can be identified by its 4-toothed mandibles, which have an even semicircular emargination between the 3 rd and 4 th tooth (Fig. 7B), and the lateral, erect, black setae on T2–6 (viewed dorsally). The male of M. texana can be identified by the apical margin of T6 (ventrad the transverse carina), which has submedian teeth that are closer to the lateral teeth than to each other (Fig. 9E), greater than 50% black pubescence on the scutum, tergites with significant bands of black pubescence, and vertex of head with greater than 50% black pubescence. This species is most similar to M. lippiae (see M. lippiae above and Taxonomic Challenges).</p><p>Notes. Megachile texana has been recorded mainly east of the divide in Montana (Fig. 1 AH). Photographs, illustrations, full morphological descriptions, and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011) and Bzdyk (2012). Sheffield and Genaro (2013) briefly made a claim of dividing M. texana from Megachile cleomis Cockerell. See Taxonomic Challenges above for a more complete discussion.</p></div>	https://treatment.plazi.org/id/03C17C29FFC3FFB073BD7D65951171E3	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC3FFB073BD7B90921A723A.text	03C17C29FFC3FFB073BD7B90921A723A.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Megachiloides) wheeleri Mitchell 1927	<div><p>Megachile (Megachiloides) wheeleri Mitchell, 1927</p><p>Megachile wheeleri Mitchell, 1927: 107 .</p><p>Megachile (Xeromegachile) wheeleri Mitchell. Butler 1965: 9 . Hurd 1979: 2066. Ivanochko 1979: 244. Mitchell 1937a: 355.</p><p>Megachile (Megachiloides) wheeleri Mitchell. Raw 2002: 21 . Scott et al. 2011: 56. Sheffield et al. 2011: 61. Reese et al. 2018: 22. Sheffield and Heron 2019: 70.</p><p>Megachile spokanensis Mitchell, 1927: 109 .</p><p>Diagnosis. The female of M. wheeleri can be identified by its 4-toothed mandibles with an asymmetrical emargination between the 3 rd and 4 th tooth, emargination deepest closer to 4 th tooth, and the widely spaced punctures on the apical half of T5, which are separated by 3–4 diameters. Females of M. wheeleri are most similar to M. manifesta (see M. manifesta above) and M. nevadensis (see M. nevadensis above and Taxonomic Challenges). The male of M. wheeleri can be identified by its wide and spatulate procoxal spine without a setal patch at the base, the protruding triangular carina on the ventral mesepisternum (viewed ventrally, directly posterior to the procoxal spine), and the quadrate metatarsomeres (viewed laterally) (Fig. 8G).</p><p>Notes. This species occurs in central Montana and the lower elevations of western Montana, west of 109° (Fig. 1 AI). This is the only member of Megachiloides besides the rarely seen M. pascoensis that has been found west of the divide. Photographs, a full morphological description, and notes on the biology of this soil-nesting species can be found in Sheffield et al. (2011).</p></div>	https://treatment.plazi.org/id/03C17C29FFC3FFB073BD7B90921A723A	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC2FFB273BD797092287334.text	03C17C29FFC2FFB273BD797092287334.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile Potentially	<div><p>Unrecorded Megachile Potentially in Montana</p><p>Eight North American species of Megachile are recorded in literature and databases occurring close to or in continuous landscapes with Montana but have not yet been recorded in the state. These species are predicted to possibly occur in Montana and may be uncovered through further faunistic work. Many species on this list (e.g., Megachile wyomingensis, Megachile latita, and Megachile hookeri) are very rarely collected and have not been critically examined since Mitchell, who may have had only one to very few specimens. All need a review as part of a comprehensive revision.</p><p>Megachile (Xanthosarus) circumcincta (Kirby) is a boreal species ranging from Alaska through British Columbia and Alberta into northern Saskatchewan (Mitchell 1935b; Sheffield et al. 2011; Sheffield 2021). It has also been recorded from the mountains of Colorado (Mitchell 1935b; Scott et al. 2011 = Megachile giliae Cockerell). With records both north and south of Montana, this species is predicted to occur widely in Montana.</p><p>Megachile (Megachiloides) hookeri Cockerell, which Mitchell states may be a color variation of M. nevadensis (Mitchell 1937a), was collected 200 km away from the Montana border in Pavillion, Wyoming (BBSL518981). It is also recorded in Lehi, Utah (Mitchell 1937a), and Colorado (Scott et al. 2011). From the Wyoming record, we predict M. hookeri may be found in the south-central badlands region of Montana near Bridger.</p><p>Discover Life shows an unvouchered Montana centroid record for Megachile (Sayapis) inimica Cresson (Discover Life 05 May 2021). There is a specimen record near Montana from Moran, Wyoming (AMNH UID653582), the identification of which was verified by Corey Smith (pers. com., 24 Mar 2021). As this species is also recorded close to the Wasatch Range in Willard, Utah (BBSL519969), we predict M. inimica may occur in southwest Montana, especially in the Centennial Valley (Beaverhead Co.) and surrounding area.</p><p>Megachile (Megachiloides) latita Mitchell was recorded in badland habitats in Worland, Wyoming and Maybell, Colorado (Mitchell 1934). As Worland is near the Montana border, we predict this species may occur in south-central Montana in the contiguous xeric area south of Bridger .</p><p>Megachile (Leptorachis) petulans Cresson has been recorded to occur widely in the eastern, southern, and central U.S. but has fewer western records (Discover Life 01 June 2021, Mitchell 1937b). As it has been recorded from Jamestown, North Dakota (Mitchell 1937b), a prairie pothole region, it would possibly be found in the prairie pothole region of northeast Montana near Plentywood and Caldera, approaching the North Dakota and Saskatchewan borders.</p><p>Megachile (Megachiloides) umatillensis (Mitchell) was recorded from Cornish, Utah, near the Wasatch Range (SEMC416330, Discover Life, 05 May 2021), in southern British Columbia (Sheffield et al. 2011; Sheffield &amp; Heron 2019), in Santa Clara, Utah, in Roggen, Colorado, and in Washington (Mitchell 1936). With records north, west, and south of Montana, we predict this species is likely to occur at least along the western or southern borders of Montana, but we have not detected it so far.</p><p>Megachile (Megachiloides) wyomingensis Mitchell was recorded from badlands near Worland, Wyoming (Mitchell1937a). It is also recorded from Sweetwater Co., Wyoming (SEMC498031) and Leota, Utah (BBSL519311), on Discover Life (01 June 2021). From these records, M. wyomingensis may possibly occur in the same area of south-central Montana, specifically south of Bridger, in the xeric landscape.</p><p>Further afield, but worth considering, specimens of Megachile (Chelostomoides) subexilis Cockerell are known from Fossil Butte National Monument, Wyoming (USGS_DRO314013), Timpanogos Cave National Monument, Utah (AMNH_BEE00079322), Provo, Utah (AMNH_BEE0007931), and Badlands National Park, South Dakota (USGS_DRO246767). This distribution suggests that this species is somewhat likely to occur in the badlands of south-central Montana near Bridger, the Black Hills region of Carter Co., and/or in the southwest corner of the state in or near the Centennial Valley (Beaverhead Co.).</p><p>Two introduced Eurasian species that may reach Montana. Megachile (Eutricharaea) pusilla Pérez is an invasive species originally from the Mediterranean region (Ghazi-Soltani et al. 2017) that is expanding its range in the U.S., including the west (Discover Life 01 June 2021), with the closest records being in Otero and Yuma Counties of Colorado (Scott et al. 2011) and in Timpanogos, Utah (AMNH_BEE00010214). Although not currently known from the state, M. pusilla could feasibly reach Montana as its range expands in the future.</p><p>One last invasive species to watch for is Megachile (Callomegachile) sculpturalis (Smith) . This native of eastern Asia is spreading from the eastern U.S. and now is established in most states east of the Mississippi River (Stevens et al. 2019). The predicted range of this species includes far western Montana with a lower probability along the Yellowstone River Valley (loc. cit.).</p></div>	https://treatment.plazi.org/id/03C17C29FFC2FFB273BD797092287334	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
03C17C29FFC0FFB373BD7CBF924A722B.text	03C17C29FFC0FFB373BD7CBF924A722B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Megachile (Eutricharaea) rotundata (Fabricius 1787)	<div><p>Notes on Megachile (Eutricharaea) rotundata and introduced Megachile Species</p><p>Megachile rotundata, or the alfalfa leafcutting bee, is native to Eurasia and was detected in the U.S. in the 1930s after being accidentally introduced (Pitts-Singer &amp; Cane 2011). Soon after, it was propagated across the western U.S. for alfalfa seed pollination, being first noted in Montana in 1969 (Gerber &amp; Akre 1969). It is managed for alfalfa seed pollination widely, including in Montana. Today, among managed species, its economic value is second only to honey bees in crop pollination (Pitts-Singer &amp; Cane 2011).</p><p>Although M. rotundata are usually thought of as managed in agricultural fields, feral populations also exist in the wild, though floral visitation appears to primarily favor Eurasian weeds (Jensen 2003; O’Neill et al. 2010; Pearce et al. 2012). Megachile rotundata accepts a diversity of nest materials and nesting sites (MacIvor &amp; Moore 2013; Sheffield 2017). In the Wolf Mountains of Montana (45.0386°N, 107.0307°W), a wild nesting aggregation was found in holes in sandstone cliffs far from alfalfa fields (ZAP pers. obs., 2019).</p><p>Stem nesting behavior in Megachile makes them more likely to be accidentally transported to new regions, as they readily nest in human-made substrates and can be transported in materials like irrigation tubing or drilled holes in wood or metal (Russo 2016; Poulsen &amp; Rasmussen 2020). These introductions could be an issue for native species as one study in California suggested that invasive Megachile could potentially compete with native Megachile for nesting sites (Cane 2003).</p><p>Megachile (Eutricharaea) apicalis Spinola is an accidentally introduced species that is now established in the U.S. (Cooper 1984; Russo 2016) and found in Montana. This species was first recorded from Montana by Kuhlman and Burrows (2017) in Missoula Co., and we record specimens from 11 counties in Montana dating from 2013 (Fig. 1C). It is already documented in much of the western U.S., and is associated with an invasive rangeland weed, Centaurea solstitialis L. ( Asteraceae) (Barthell et al. 2001; McIver et al. 2009; Sheffield et al. 2011). In Montana, Kuhlman and Burrows (2017) suggest that M. apicalis may be using Centaurea stoebe L. ( Asteraceae), a Montana weed that is a relative of C. solstitialis .</p></div>	https://treatment.plazi.org/id/03C17C29FFC0FFB373BD7CBF924A722B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Pritchard, Zoe A.;Ivie, Michael A.;O’Neill, Kevin M.;Delphia, Casey M.	Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M., Delphia, Casey M. (2025): A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification. Zootaxa 5683 (1): 1-51, DOI: 10.11646/zootaxa.5683.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
