Resumo. The genus Quadraseta Brennan, 1970 (Trombiculidae) is distributed in South American, with a few records from Central America. The larvae (chiggers) are primarily mammal parasites, with one species from birds. Examination of unidentified material at US National Insect and Mite Collection revealed five species to this genus: Q. brasiliensis Goff & Gettinger, 1989, Q. falconensis Goff & Brennan, 1977, Q. flochi (Brennan & Jones, 1960), Q. mackenziei (Yunker & Brennan 1964), and Q. mirandae Goff & Brennan, 1977. This study resulted in new South American localities and host records for these species.