Megachile (Xanthosarus) latimanus Say, 1823

Megachile latimanus Say, 1823: 81 .

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.

Megachile (Delomegachile) vidua Smith, 1853: 192 . Mitchell 1935b: 200.

Megachile latimanus / perihirta; Pearce 2008: 57.

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.

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).