Key to Species of Rhyssomegachile FEMALES 1. Carina behind gena continuing onto vertex (fig. 15C, D); dorsum of mesosoma with long (≥2.0× OD), light reddish-brown setae (fig. 15B, C); forewing yellowish with yellow to light brown veins (fig. 15B) ....................... ............................. M. guayaqui Schrottky — Carina behind gena not continuing onto vertex; dorsum of mesosoma with shorter (≥1.0× OD), yellowish or grayish setae; forewing brownish with dark brown veins........2 2(1).Disc of mesoscutum with punctures distinctly spaced, not contiguous, separated by 1–2× a puncture width (fig. 20D) ................. ............................................... M. urbana Smith — Disc of mesoscutum with punctures contiguous or nearly so (fig. 4A) ..................... 3 3(2).Ventral surface of mesepisternum and fore- and middle legs with coxae, trochanters, base of femora, and outer surfaces of tibiae and basitarsi densely covered by corkscrewlike setae (fig. 4D, E); clypeus and supraclypeal area finely and densely punctate (fig. 16B); T2–T5 without apical fasciae (fig. 16D); T6 with short, appressed brownishgray setae, without longer, erect setae .......... ......................... M. kartaboensis Mitchell — Ventral surface of mesepisternum and all legs distinctly covered by thick, minutely branched, and apically curved setae (fig. 17C); clypeus and supraclypeal area coarsely punctate (fig. 17A); T2–T5 each with apical fasciae at least laterally (fig. 17D, E); T6 covered mostly by short, appressed yellowish setae from which scattered, longer, erect setae arise ................... M. simillima Smith

Published as part of Gonzalez, Victor H., Griswold, Terry & Engel, Michael S., 2018, South American Leaf-Cutter Bees (Genus Megachile) Of The Subgenera Rhyssomegachile And Zonomegachile, With Two New Subgenera (Hymenoptera: Megachilidae), pp. 1-73 in Bulletin of the American Museum of Natural History 2018 (425) on pages 1-73, DOI: 10.1206/00030090-425.1.1, http://zenodo.org/record/4613364