Megachile (Megachiloides) subnigra Cresson, 1879

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 : 40-41

Megachile (Megachiloides) subnigra Cresson, 1879

Megachile subnigra Cresson, 1879: 208 .

Megachile (Xeromegachile) subnigra ; Mitchell 1937a: 364; 1944: 138. Hurd 1979: 2065. Ivanochko 1979: 252.

Megachile (Megachiloides) subnigra ; Raw 2002: 21 . Scott et al. 2011: 56. Sheffield et al. 2011. Reese et al. 2018: 22 . Delphia et al. 2019a: 25 . Sheffield and Heron 2019: 70.

Megachile (Xeromegachile) angelica Mitchell, 1934: 318 .

Megachile (Xeromegachile) blaisdelli Mitchell, 1934: 336 .

Megachile (Xeromegachile) moschata Mitchell, 1934: 338 .

Diagnosis. The female of M. subnigra can be identified by its all-black scopal setae on S2–6 and 4-toothed mandibles with a pointed basal mandibular tooth ( Fig. 7B ). The female of M. subnigra is most similar to M. gemula , which has reddish-brown scopal setae on S2–6 and a truncate basal mandibular tooth ( Fig. 7E ). For further details on identification issues see Taxonomic Challenges. The male of M. subnigra can be identified by the mostly black pubescence on the mid and hind legs, cream to yellow colored protarsi, and the wide, spatulate procoxal spine ( Fig. 8I ) with a short suberect patch of setae at the base.

Notes. Megachile subnigra is known from the southern half of central Montana, in the upper Yellowstone and upper Missouri drainages ( Fig. 1 AG). Photographs, a full morphological description, and notes on the biology of this ground-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 7. Female Megachile characters. (A–H) Anterolateral view of mandible, (I–N) Lateral view of metasoma, tergites 4–6, (O) Lateral view of tergites on M. dakotensis, and (P) Lateral view of head with pronounced tooth on the posterior genal margin on M. pugnata.

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.