1	A. Occipital carina present; Neotropical	Helconichia
–	B. Occipital carina absent; widespread	2
2(1)	A. Epicnemial carina present; Neotropical	Muesonia
–	B. Epicnemial carina absent; widespread	3
3(2)	A. Notaulus smooth; widespread	4
–	B. Notaulus sculptured, at least some crenulae anteriorly; Neotropical	5
4(3)	A. First median tergite smooth, lacking lateral carinae; widespread, common	Proterops
–	B. First median tergite with lateral carinae; Neotropical, rare	Michener gen. nov.
5(3)	A. Longitudinal carina on propleuron present. AA. Petiole with a pair of weak, short, parallel, longitudinal carinae. AAA. Female without patch of setae at apex of hypopygium; Neotropical	Masonbeckia
–	B. Longitudinal carina of propleuron absent. BB. Petiole with pair of strong, converging, longitudinal carinae that form a spoon-shaped depression at the base of the tergum. BBB. Female with patch of setae at apex of hypopygium; Neotropical	Hebichneutes