1	Females	2
–	Males	6
2(1)	Scopa absent; metasoma tapering from near base to narrow, apex often acutely pointed; cleptoparasite	Coelioxys (Allocoelioxys)
–	Scopa present on metasomal sterna two through five or six; metasoma not distinctly tapering throughout its length; free living	3
3(2)	Sixth metasomal sternum with a fringe of branched setae on or near apical margin; mandible with cutting edge in at least one interspace, sometimes hidden behind margin of interspace	4
–	Sixth metasomal sternum without apical fringe of branched setae; mandible without cutting edges between teeth	5
4(3)	Mandible five- or six-toothed, teeth (except first) similar and with similarly-shaped, incomplete cutting edges in second and third (and sometimes fourth) interspaces; apices of mandibular teeth roughly equidistant from nearest neighbors; preapical transverse mandibular groove distinct and filled with short, fine, pale setae	Megachile (Creightonella)
–	Mandible four- to five-toothed, teeth above first of different shapes and cutting edges often of different shapes; apices of mandibular teeth commonly separated from nearest neighbors by different distances; preapical transverse mandibular groove, if present, not filled with short, pale setae	Megachile (Eutricharaea)
5(3)	Distal margin of clypeus irregularly rounded (rarely weakly emarginate medially), usually strongly crenulate, produced well over base of labrum, not thickened; mandible usually slender with apical margin strongly oblique; head little developed posteriorly, ocelloccipital distance thus not greater than interocellar distance	Chalicodoma (Chalicodoma)
–	Distal margin of clypeus truncate, not crenulate, often not much produced over base of labrum, but if rounded and somewhat crenulate, then margin thickened and impunctate; head usually much developed posteriorly, ocelloccipital distance thus greater than interocellar distance	Chalicodoma (Pseudomegachile)
6(1)	Sixth metasomal tergum with multispinose preapical carina, with two pairs of long, preapical spines, each spine of upper pair sometimes divided into two, or crenulate, rounded, or fused to other spine of pair; cleptoparasite	Coelioxys (Allocoelioxys)
–	Sixth metasomal tergum with preapical carina not as above, often crenulate, medially emarginate, or sometimes reduced to two spines; free living	7
7(6)	Fifth and sometimes sixth metasomal sterna exposed and generally similar to preceding sterna (sometimes fifth sternum largely hidden but sixth sternum exposed); lateral extremity of carina of sixth tergum directed basad, away from apical margin of tergum	Megachile (Creightonella)
–	Fifth and sixth metasomal sterna retracted, variously modified, less sclerotized, less punctate, and less setose than first to fourth sterna; lateral extremity of carina of sixth tergum absent or directed toward lateral extremity of apical margin of tergum	8
8(7)	Eighth metasomal sternum without marginal setae but discal setae sometimes extending beyond margin laterally; metasoma usually less strongly convex and usually less than twice as long as wide	Megachile (Eutricharaea)
–	Eighth metasomal sternum often with lateral marginal setae; metasoma commonly strongly convex and twice as long as wide or more	9
9(8)	Toothed margin of mandible (three- to four-toothed) strongly oblique, nearly as long as distance from upper tooth to mandibular base; seventh metasomal tergum with narrow, median, apically-truncate projection extending well beyond teeth of sixth tergal carina; apex of gonostylus asetose or with very short, poorly-branched to simple setae	Chalicodoma (Chalicodoma)
–	Toothed margin of mandible (three-toothed) less oblique, much shorter than distance from upper tooth to mandibular base; seventh metasomal tergum a low sclerite largely hidden behind sixth tergum, sometimes produced to small median spine; apex of gonostylus often with long, densely-branched setae on medial margin	Chalicodoma (Pseudomegachile)