Megachile (Litomegachile) brevis Say, 1837

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.

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.

Megachile brevis var. nupta; Mitchell 1935a: 13.

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).

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).