_Specimens examined._--(10). MEXICO, _Sinaloa_: 36 mi. N Mazatlan, UIMNH 38094-96, 67061 (holotype), 71970-74; 65 mi. N Mazatlan, LACM 13773. =Syrrhophus modestus= Taylor _Syrrhophus modestus_ Taylor, 1942:304-06, pl. 29 [Holotype.--FMNH 100048 (formerly EHT-HMS 3756), from Hacienda Paso del Rio, Colima, Mexico; collected on July 8, 1935, by Hobart M. Smith]. Smith and Taylor, 1948:49-50. _Syrrhophus modestus modestus_: Duellman, 1958:2-5, 7, 14, pl. 1, fig. 1. Gorham, 1966:166. _Diagnosis._--Small frogs, males 15.8-20.1 mm. snout-vent length, single female 18.5 mm.; vocal slits present in males; finger tips widely expanded; first finger shorter than second; inner metatarsal tubercle about three times size of outer; skin of dorsum shagreened, that of venter smooth; tympanum concealed; pale cream in preservative with dark brown spots; limbs banded; bands on forearm and thigh poorly developed or absent; interorbital bar absent. _Remarks._--The tympanum is concealed in _S. modestus_, _S. nivocolimae_, _S. pallidus_, _S. teretistes_, and to a lesser degree in _S. interorbitalis_. However, if the specimen is permitted to dry slightly, the annulus tympanicus becomes visible through the skin and a tympanum/eye ratio can be computed. One of the few cases of sympatry within the genus _Syrrhophus_ involves this species; _modestus_ and _nivocolimae_ are known to be sympatric at one locality in southwestern Jalisco, Mexico. Duellman (1958) used the trinomial for this population and named a new subspecies, _pallidus_, from Nayarit. I consider _pallidus_ to be specifically distinct from _modestus_ because there is no evidence of genetic exchange, and there is no overlap in the distinguishing morphological features. I do consider the two populations to be closely related but feel the interrelationships between _modestus_, _pallidus_, _nivocolimae_, and _teretistes_ are more complex than would be indicated by the use of trinomials. The sympatric occurrence of _modestus_ and _nivocolimae_ is significant; morphologically, they might otherwise be regarded as subspecies. Although allopatric, similar arguments could be advanced for the morphologically similar _pallidus_ and _teretistes_. The four are here afforded species rank since morphological similarity and allopatry are not sufficient grounds for the assumption of genetic exchange. [Illustration: FIG. 19: _Syrrhophus modestus_ [left, UMMZ 115447 (WED 11155)] and _S. pallidus_ (right, UMMZ 115453). x2.2.] _Etymology._--Latin, meaning unassuming, modest, in reference to the small size of the species. _Distribution._--Low elevations (up to 700 meters) in the lowlands and foothills of Colima and southwestern Jalisco, Mexico (Fig. 20).