Investigations of the chiggers from mammals taken in the Mexican states of Baja California Norte, Sonora, Sinaloa and Durango, revealed seven species of Euschoengastia. Three of these species are new and are described below and the other four, Euschoengastia californica, E. criceticola, E. otophila and E. radfordi, are reported from Mexico for the first time.
This genus, as currently defined by Vercammen-Grandjean (1960), contains approximately 50 species. Most of the species occur in the Nearctic Region and Euschoengastia barrerai Hoffmann (1960) is the only species reported previously from Mexico. A closely related genus and species, Anahuacia robertraubi Hoffmann (1963), also has been described from larvae found on mammals from the vicinity of Mexico City, at the southern border of the Mexican plateau, in temperate habitats. Our seven species also were taken in the Nearctic Region, including the Sonoran Desert, the Oak-Chaparral and the Oak-Pine Plant Associations. The localities, hosts, dates and notes on habitats are included in the discussion of each species.