Certain diagnostic characters of this species as given by Taylor (1943a:50) and Taylor and Smith (1945:598) are in need of revision. _Hylella sumichrasti_ has been characterized as having no vocal sac, rarely having vomerine teeth, and as having a relatively smooth throat. The vocal sac in breeding males is quite evident; it is single, median, and when expanded, spherical. The openings into the vocal sac are narrow slits along the inner posterior border of the jaw rami. Of 151 specimens studied, 74 have vomerine ridges between the choanae, and 36 of these have one to three teeth on each ridge. The belly and undersurfaces of the thighs are granular; the throat is only somewhat less so. The granular condition may be correlated with breeding, for specimens obtained from bromeliads in the dry season had rather smooth throats. It seems that the vocal sac atrophys in the non-breeding season. These seasonal changes may account for the diagnoses given by Taylor (_op. cit._) and Taylor and Smith (_op. cit._); likewise, since many of the specimens obtained by Smith in the dry season were juveniles and subadults, the development of the vomerine ridges could not be diagnosed properly. The range of this species encompasses the Pacific slopes of the Isthmus of Tehuantepec eastward to the upper Cintalapa Valley and vicinity of Tonala in western Chiapas. Priscilla Starrett collected tadpoles of _H. sumichrasti_ from a stream 19 km. N of Arriaga, Chiapas. These limited observations on the ecology of this frog suggest that it breeds in the fast-moving streams of the Pacific slopes, and that it seeks shelter in arboreal bromeliads during the dry season. =Phrynohyas modesta= Taylor and Smith _Oaxaca_: Tuxtepec. _Veracruz_: 20 km. S of Jesus Carranza; 20 km. ENE of Jesus Carranza (2); Minatitlan. I have not collected this species in the isthmus. The locality records indicate that the range is discontinuous (Duellman, 1956:27). The species occurs on the humid Pacific slopes from south-central Chiapas eastward to El Salvador and on the humid Gulf lowlands from southern Veracruz eastward into Tabasco, but is unknown from the dry Pacific slopes and plains in the isthmus. The acquisition of several specimens of this species in southern Veracruz, Tabasco, and Oaxaca, together with a knowledge of the variation displayed by _Phrynohyas spilomma_, suggests that _modesta_ may be a color variety of _spilomma_. =Phrynohyas spilomma= Cope _Oaxaca_: Tapanatepec (3). _Veracruz_: Amatitlan (12); Chacaltianguis (2); Ciudad Aleman (6); Cosamaloapan; Novillero (3).