Megachile (Xanthosarus) perihirta Cockerell, 1898

Megachile perihirta Cockerell, 1898: 126 . Drons 2012: 58. Adhikari et al. 2019: Supplementary Table S4.

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.

Megachile fortis, not Cresson, 1872 (misidentification); Simanonok 2018: 89.

Megachile circumcincta, not Kirby, 1802 (misidentification); Adhikari et al. 2019: Supplementary Table S4.

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).

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).