Megachile (Eutricharaea) apicalis Spinola, 1808

Megachile apicalis Spinola, 1808: 259 .

Megachile (Eutricharaea) apicalis; Mitchell 1962: 120. Hurd 1979: 2057. Cooper 1984: 225. Sheffield et al. 2011: 29. Kuhlman and Burrows 2017: 12. Reese et al. 2018: 21. Delphia et al. 2019a: 24. Sheffield and Heron 2019: 69.

Megachile virginiana Mitchell, 1926a: 113 .

Diagnosis. The female of M. apicalis can be identified by the white apical setal bands on S2–6 (Fig. 6A), black scopal setae on S5, and lateral, ovate fovea on T2 and T3. Females of M. apicalis are most similar to M. rotundata, which have white scopal setae on S5 and lateral, ovate fovea on T2 only. The male of M. apicalis can be distinguished by the lateral, ovate fovea on T2 and T3. Males of M. apicalis are most similar to M. rotundata, which have lateral, ovate fovea on T2 only.

Notes. Megachile apicalis is an accidentally introduced species in the United States, first collected in Montana in 2013 from localities in Deer Lodge, Sanders, and Lake Counties. It was first documented in the literature by Kuhlman & Burrows (2017). This species may contribute to pollination of the invasive yellow star-thistle ( Centaurea solstitialis), though not as strongly as A. mellifera (Barthell et al. 2001) . Megachile apicalis is currently present in western Montana but is expected to spread further (Fig. 1C). It is established on both coasts of the U.S. and seems to be moving into Montana from the Pacific Northwest region (see Discussion: Notes on Megachile (Eutricharaea) rotundata and Introduced Megachile Species). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).