Saguinus midas occurs north of the Rio Amazonas and east of the Rios Negro and Branco in Brazil, extending north and east to the coast of Amapá and the Guianas (Napier 1976). It is also evidently absent from a large part of central Guyana. It does not occur around the city of Manaus, the domain of Saguinus bicolor, and shows only a narrow zone where it mixes with this species on the periphery of S. bicolor's range (Ayres et al. 1980). The situation is probably the same with the two Saguinus martinsi subspecies. In the north of its range, Saguinus midas occurs in French Guiana, Suriname and Guyana (Husson 1957), but is largely restricted to the east of the Essequibo River (Norconk et al. 1996). It would seem that it has crossed the Essequibo along the lower reaches of the river, judging by sightings at Hosororo Hill on the Venezuelan border and from Waraputa on the west bank of the Essequibo just south of Mabura Hill (Sussman and Phillips-Conroy 1995; Norconk et al. 1996). There had been no reports of callitrichids occurring in Venezuela (Handley 1976; Bodini and Pérez-Hernández 1987), until Linares (1998) indicated its occurrence in eastern Bolívar. Urbani (2006), on the other hand, was unable to find evidence of the presence of S. midas in Bolívar, and concluded that it is not present there or is extremely rare.