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).