The genera Trichopetalum Harger, 1872, Zygonopus Ryder, 1881 and Scoterpes Cope, 1872 are revised. Illustrations are provided for all but one species, and distributions are mapped. The first known authentic chordeumatidan spermatophores are described for Trichopetalum dux (Chamberlin), 1940. The production of a sticky secretion from the bases of the segmental setae, possibly defensive in function, is also described. The new subfamily Mexiterpetinae is established for the genus Mexiterpes Causey, 1963; the remaining genera of Trichopetalidae are grouped in subfamily Trichopetalinae Verhoeff, 1914 (tribe Scoterpetini Causey, 1969, n. syn.). Trichopetalum consists of seven species, all surface-dwelling or troglophilic: lunatum Harger, 1872, uncum Cook & Collins, 1895, dux (Chamberlin), 1940, montis Chamberlin, 1951, stannardi (Causey), 1951, dickbrucei n. sp. and jerryblatti n. sp. Zygonopus is resurrected from synonymy with Trichopetalum; it contains four troglobiotic species: whitei Ryder, 1881 (for which a neotype specimen is designated), krekeleri Causey, 1960, packardi Causey, 1960 and weyeriensis Causey, 1960. Scoterpes likewise is made up entirely of troglobiotic species, including copei (Packard), 1881, austrinus Loomis, 1943, nudus Chamberlin, 1946, ventus Shear, 1972, syntheticus (Shear), 1972, sollmani Lewis, 2000, and the following new species: alabama, hesperus, jackdanieli, musicarustica, stewartpecki, tombarri, tricorner and willreevesi. It is likely that at least S. copei and S. ventus are “superspecies,” consisting of numerous genetically isolated populations, which await study with molecular and/or morphometric methods.