Nearly every specimen examined was infested with chiggers of the genus _Hannemania_. The greatest concentrations are on the venter, in the groin, and on the thighs. Many specimens have chiggers on the digits and tarsi. The same, or a related, chigger was found on many specimens of _Syrrhophus marnockii_ and a few _S. verrucipes_, but on no other species of the genus. Mr. Willy Wrenn told me that he has seen heavy infestations of _Hannemania_ on _Syrrhophus pallidus_. Infestation by _Hannemania_ probably reflects similar ecologies rather than close relationships. [Illustration: FIG. 10: Distribution of _Syrrhophus guttilatus_.] _Etymology._--Latin, _guttula_, meaning spotting or flecking, in reference to the color pattern. _Distribution._--Moderate to intermediate elevations (600 to 2000 m.) along the Sierra Madre Oriental from the Big Bend Region of Texas to Guanajuato, Mexico (Fig. 10). _Specimens examined._--(32) TEXAS, _Brewster Co._: Juniper Canyon, Chisos Mts., FMNH 27361 (holotype of _S. gaigeae_), 27360, 27362-63, MCZ 15346, 27801, UMMZ 66080, 66082, 66085-91, USNM 76876; Upper Green Gulch, TCWC 15943. MEXICO: _Coahuila_: 8 km. S Saltillo, UIMNH 55518-21. _Guanajuato_: Guanajuato, USNM 9888 (holotype of _Malachulodes guttilatus_); 8 km. E Guanajuato, AMNH 73425; Cerro Cubilete, AMNH 73424. _Nuevo Leon_: 3 km. S Galeana, JDL 1215 (skeleton), UIMNH 58204; 24 km. SW Galeana. 1575 m., USNM 108594 (holotype of _Syrrhophus smithi_). _San Luis Potosi_: 5 km. SW San Luis Potosi, UIMNH 7807 (holotype of _S. petrophilus_). _Tamaulipas_: 1.6 km. NW La Joya de Salas, 1530 m., UMMZ 110736 (4). =Syrrhophus marnockii= Cope _Syrrhophus marnockii_ Cope, 1878:253 [Syntypes.--ANSP 10765-68, from "near San Antonio," Bexar Co., Texas; collected by G. W. Marnock]. _Syrrhophus marnocki_: Yarrow, 1882:24, 193. Milstead, Mecham, and McClintock, 1950:550. _Diagnosis._--Medium-sized frogs, males 18.4-28.9 mm. snout-vent, females 20.4-35.4 mm. snout-vent length; vocal slits in males; digital tips widened (Fig. 1); first and second fingers equal; skin of dorsum smooth to weakly pustular, that of venter smooth; snout blunt, rounded; diameter of tympanum 47.2-68.3 per cent that of eye in males, 45.8-73.3 in females; dorsum tan to light brown in preservative with rusty-brown flecks, venter white; ground color green in life; thighs banded; interorbital bar absent. _Remarks._--Specimens from the southern edge of the Edwards Plateau and the eastern edge of the Stockton Plateau have larger flecks on the back that tend to form a vermiculate pattern like that of _S. guttilatus_. The vermiculation is never well developed (see plate 38 in Conant, 1958). Most of the specimens from the Edwards Plateau have a punctate pattern (Fig. 9). Fossils are known from the Sangamon interglacial deposits in Foard and Knox Counties, Texas (Lynch, 1964; Tihen, 1960). _Etymology._--A patronym for the collector of the type specimens.