_Diagnosis._--Medium sized frogs, males 22.6-28.5 mm. snout-vent, females 21.1-29.4 mm. snout-vent length; vocal slits present in males; finger tips slightly expanded, truncate in outline; inner metatarsal tubercle less than twice the size of outer; skin of dorsum smooth to shagreened, that of venter smooth; tympanum 36.5-54.0 per cent diameter of eye; dorsum dark brown with large or small light brown, orange-brown, or yellowish spots or blotches; limbs banded; interorbital bar absent. [Illustration: FIG. 15: Dicegrams of ear size relative to eye diameter in the two subspecies of _Syrrhophus pipilans_. N = 17 in _nebulosus_, 18 in _pipilans_.] _Remarks._--Two subspecies were recognized by Duellman (1958). Previously both had been treated as species. The two populations were distinguished on the basis of color pattern and the size of the tympanum. Measurements of 17 males of _S. p. nebulosus_ from central Chiapas and 18 males of _S. p. pipilans_ from southcentral Oaxaca and Guerrero, Mexico, demonstrates that the supposed difference in tympanum size is not significant (Fig. 15). There is, however, a tendency for the western population of _S. pipilans_ to have larger tympani. Based on the present examination of 112 specimens of this species the two populations are held to be sufficiently distinct to warrant taxonomic recognition as subspecies (Fig. 16). [Illustration: FIG. 16: _Syrrhophus pipilans nebulosus_ (left, KU 58908) and _S. p. pipilans_ (right, KU 86885). x2.7.] The parotoid glands attributed to this species by Taylor (1940c:95) are merely the superficial expression of the _m. depressor mandibulae_ and scapula. No true glands are present in the parotoid region. =Syrrhophus pipilans nebulosus= Taylor _Syrrhophus nebulosus_ Taylor, 1943:353-55, pl. 27, figs. 3-5 [Holotype.--FMNH 100095 (formerly EHT-HMS 3774), near Tonola, Chiapas, Mexico; collected on August 27, 1935, by Hobart M. Smith and Edward H. Taylor]. Smith and Taylor, 1948:49, 51. _Syrrhophus pipilans nebulosus_: Duellman, 1958:2-4, 9, 12, 14. Stuart, 1963:32-33. Gorham, 1966:166-67. _Diagnosis._--Diameter of tympanum 36.6-47.8 per cent that of eye; dorsum dark brown with numerous small light brown to yellowish spots. _Remarks._--The distribution of this subspecies is adequately described by Duellman (1958). Fouquette (1960) described the vocalization of this frog. _Etymology._--Latin, _nebula_, in reference to the clouded dorsal pattern. _Distribution._--Low to moderate elevations along the Pacific versant of Chiapas and in the Grijalva valley of Chiapas and Guatemala (Fig. 17).