_Diagnosis and definition._--Small frogs (20 to 40 mm. snout-vent length) having undilated digital tips lacking transverse grooves; lumbo-inguinal or inguinal glands absent; plantar supernumerary tubercles present, extending between metatarsal tubercles; tarsus bearing spinelike tubercle on inner edge; toes free; terminal phalanges pointed; sternum bearing bony style; spenethmoid not truncate anteriorly; nasals in contact medially; maxillary and quadratojugal in articular contact; anterior arm of squamosal not in contact with maxillary; dermal cranial elements not involved in integumentary-cranial co-ossification; prevomers moderate in size, lacking teeth; maxillary and premaxillary bones edentate; occipital condyles separated; tadpole free living. _Composition._--Four nominal species (_E. petersi_, _E. pustulatus_, _E. pustulosus_ and _E. schereri_). _Distribution._--Central Veracruz and eastern Oaxaca, Mexico, to Trinidad, Bolivia, and Peru, east of the Andes. _Etymology._--Greek (_engys_ + _stoma_) meaning narrow-mouthed. Genus ~Hylactophryne~ new genus _Type-species._--_Hylodes augusti_ Duges, 1879 _Diagnosis and definition._--Medium to large frogs (37 to 94 mm. snout-vent length) having undilated digital tips lacking terminal grooves; lumbo-inguinal or inguinal glands absent; plantar supernumerary tubercles present, prominent, extending to but not between metatarsal tubercles; tarsus lacking tubercles or folds; toes free of webbing; terminal phalanges knob-shaped, lacking elongate lateral expansions; sternum cartilaginous, lacking bony style; sphenethmoid truncate anteriorly; nasals in contact medially; maxillary and quadratojugal in articular contact; anterior arm of squamosal not in contact with maxillary; dermal cranial elements not involved in integumentary-cranial co-ossification; prevomers large, bearing dentigerous processes; maxillary and premaxillary bones dentate; occipital condyles separated; development direct. _Composition._--Two species, _H. augusti_ and _H. tarahumarensis_, the former composed of four subspecies (Zweifel, 1956). _Distribution._--From Arizona, New Mexico, and Texas to Guerrero and Puebla, Mexico, and a relict population on Cerro Quingola (just west of the Isthmus of Tehuantepec, Mexico). _Etymology._--Greek (_hylactor_ + _phryne_) meaning barking toad; in reference to the voice and common name. Genus ~Leptodactylus~ Fitzinger, 1826 _Type-species._--_Leptodactylus typhonia_ Fitzinger, 1826