A review of the pseudoscorpion family Ideoroncidae in North and South America has revealed seven genera and 43 species. The genus Albiorix occurs in xeric environments in western USA and in Mexico, with two outlying species in Chile and Argentina. It includes 18 species, including five new species from Mexico (A. meraculus, A. minor, A. oaxaca, A. puebla and A. rosario), and three from USA (A. gertschi, A. sarahae and A. vigintus). Albiorix bolivari is treated as a junior synonym of A. retrodentatus. The genus Ideoroncus has nine species and is endemic to southern Brazil and Paraguay. Pseudalbiorix has four species and occurs in Central America and western Cuba. Typhloroncus has six species from Mexico and U.S. Virgin Islands, including the new species T. planodentatus from Mexico. Xorilbia has three species and occurs in the Amazonian rainforest ecosystems of northern Brazil and southern Venezuela. Two new genera are described: Mahnertius Harvey & Muchmore for the new species M. stipodentatus (type species) and M. hadrodentatus, both from Colombia; and Muchmoreus Harvey for the new species M. ignotus (type species) from Mexico. Several keys are provided, including one to separate the New World genera, and others to distinguish the species of each genus (apart from the monotypic Muchmoreus). The post-embryonic development of New World ideoroncids is reviewed, particularly the trichobothrial patterns of nymphs and adults.