Megachile (Sayapis) mellitarsis 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 : 36

Megachile (Sayapis) mellitarsis Cresson, 1878

Megachile mellitarsis Cresson, 1878: 121 .

Megachile (Sayapis) mellitarsis ; Mitchell 1937c: 194. Hurd 1979: 2071. Ivanochko 1979: 328. Scott et al. 2011: 56. Sheffield et al. 2011: 66. Sheffield and Heron 2019: 70.

Diagnosis. The female of M. mellitarsis can be distinguished by the two broadly incurved emarginations on its clypeal margin ( Fig. 6E ), 4-toothed mandibles with evenly deep emarginations between all teeth, and reddish-brown tarsi contrasting the black tibia on the legs. The male of M. mellitarsis can be distinguished by the thin, narrowly pointed procoxal spine ( Fig. 8H ), orangish brown meso- and metatarsi, and the distinctly yellow protarsi with elongated apical dilation that reaches apex of the 3 rd tarsomere. The male of M. mellitarsis is closest to M. pugnata and M. fidelis , both of which have front basitarsi with apical dilation not reaching 3 rd tarsomere. For more details on identification issues see Taxonomic Challenges.

Notes. This species is a new state record for Montana. Other than a record from British Columbia’s Western Interior Basin ( Sheffield 2019), this dry-land species is at the northern edge of its known range in southern Montana ( Fig. 1U ). Photographs, a full morphological description, and notes on the biology of this 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.