Megachile ( Sayapis ) fidelis Cresson, 1878

Megachile ( Sayapis) fidelis Cresson, 1878 View in CoL

Megachile fidelis Cresson, 1878: 120 View in CoL . Drons 2012: 58.

Megachile ( Sayapis) fidelis View in CoL ; 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 View Cited Treatment . Sheffield and Heron 2019: 70. Engel 2020: 10.

Diagnosis. The female of M. fidelis is distinguished by its subparallel metasoma (viewed dorsally) ( Fig. 6C View FIGURE 6 ) and clypeal margin with two prominent, wide, lateral tubercles surrounding a median triangular tubercle ( Fig. 6F View FIGURE 6 ), 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 View FIGURE 8 ) and its widely expanded and ventrally excavated probasitarsus ( Fig. 8B View FIGURE 8 ) 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.

Notes. This species has been recorded mainly in western Montana ( Fig. 1K View Figure 1 ), 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).