Megachile (Sayapis) fidelis Cresson, 1878

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), pp. 1-51 : 32

Megachile (Sayapis) fidelis Cresson, 1878

Megachile fidelis Cresson, 1878: 120 . Drons 2012: 58.

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.

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. 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).

Figures

FIGURE 1. County-level distribution of each Megachile species in Montana. Females identified as Megachile latimanus/ Megachile perihirta (and data without recorded specimen sexes) are counted here as M. perihirta as they are not distinguishable from one another in Montana. Males identified as Megachile lapponica/Megachile relativa (and data without recorded specimen sexes) are counted here as M. relativa as they are not distinguishable from one another in Montana. Mitchell county records are included on maps but not in specimen counts. Two specimens did not have county-level localities and are not included in maps but are included in specimen counts.

FIGURE 6. Female Megachile characters. (A) Ventral view of metasoma with white apical setal bands on S2–6, (B) Dorsal view of rounded metasoma, widest at T2–3, (C) Dorsal view of subparallel metasoma, (D–H) Anterior view of clypeus: (D) M. apicalis, (E) M. mellitarsis, (F) M. fidelis, (G) M. lippiae, (H) M. coquilletti, (I) Lateral view of mandible gradually tapering in width towards apex, (J) Lateral view of mandible with base square-shaped with parallel sides for a distance as long as wide, then tapering apically, and (K) Lateral view of mandible square basally, with sides parallel for approximately ⅓ the length of mandible, then tapering apically.

FIGURE 8. Male Megachile characters. (A) Probasitarsus not expanded or excavated ventrally, (B) Probasitarsus widely expanded and excavated ventrally, (C–E) Anterior view of mesobasitarsus and mesotibia, (F) Lateral view of triangular metatarsomeres on M. manifesta, (G) Lateral view of quadrate metatarsomeres on M. wheeleri, (H) Ventral view of procoxal spine, longer than wide, (I) Ventral view of procoxal spine, wide and spatulate, (J–L) Dorsal view of vertex of head: (J) Ocelloccipital distance longer than ocellocular distance, (K) Ocelloccipital distance equal to ocellocular distance, and (L) Ocelloccipital distance shorter than ocellocular distance.