Four distinct genera, forming two monophyletic groups, are basal in the phylogeny of the North American vaejovid scorpion subfamily Syntropinae Kraepelin, 1905: Konetontli González-Santillán and Prendini, 2013; Maaykuyak González-Santillán and Prendini, 2013; Syntropis Kraepelin, 1900; and Vizcaino González-Santillán and Prendini, 2013. All except the species of Konetontli, treated elsewhere, are revised in the present contribution. The two species of Maaykuyak, three species of Syntropis, and monotypic Vizcaino are redescribed; the adults of Syntropis williamsi Soleglad et al., 2007, described for the first time; keys to identification of the species of Maaykuyak and Syntropis presented; and new locality records and updated distribution maps provided for all species covered.