The holotype of Drymobius heathii Cope (now Mastigodryas heathii) has remained unrecognized since the species was described in 1876. A review of specimens and associated data in the Academy of Natural Sciences of Philadelphia shows that one specimen, ANSP 11544, is very likely the holotype of this species. The presumptive holotype is redescribed and the coloration in life and natural history and other data for this species from northern Peru are presented. Mastigodryas heathii occurs in lowland coastal desert scrub and dry deciduous forests of the Pacific slope and interandean valleys. Its diet includes frogs, lizards, and rodents.