Two new species of schoengastiine chiggers (Acari: Trombiculidae) from Brazil and rediagnosis of Arisocerus Brennan, 1970.

Colicus spinosus Goff & Gettinger, n. sp., is described from Marmosa agilis. Quadraseta brasiliensis Goff & Gettinger, n. sp., is described from Marmosa agilis, Monodelphis americana, and Oryzomys capito. All specimens were collected in central Brazil. The diagnosis of the genus Arisocerus Brennan, 1970, is corrected to describe the setation of the palpal tarsus as 7BS rather than 6BS as listed in the original description.