_Remarks._--Martin (1958) was the first author to point out that _S. campi_ was probably a subspecies of the more southern _S. cystignathoides_. Various references in the literature might lead one to believe that the two were sympatric over much of northeastern Mexico; this error was created by the use of a single character (condition of the skin of the venter) to characterize the two populations. Specimens from southern Texas have a smooth venter, lack interorbital bars and have, in general, a brown ground color, whereas specimens from central Veracruz have an areolate venter, interorbital light and dark bars and a yellow ground color. In southern Tamaulipas and eastern San Luis Potosi, these characters vary discordantly, thereby strongly suggesting that the two populations intergrade. Both populations agree in other morphological characters; therefore, they are here treated as geographic variants. _Etymology._--Named for the collector of the type specimens, Mr. R. D. Camp of Brownsville, Texas. _Distribution._--Lower Rio Grande embayment in Texas to central Nuevo Leon and Tamaulipas, Mexico. Intergrades are known from southern Tamaulipas and adjacent San Luis Potosi, Mexico (Fig. 5). _Specimens examined._--(113) TEXAS, Cameron Co.: MCZ 10277-85, 10286 (10); Brownsville, AMNH 3215, 3218-20, 3221 (3), 5376, 62117, FMNH 105336, KU 8135-39, MCZ 3738-42, 3743 (10), TCWC 5908, 7139, TNHC 92-94, 20909, UMMZ 51760, 54031 (5), USNM 52290 (holotype); 22 mi. SE Brownsville, TNMC 14223; 8 mi. SW Brownsville, UMMZ 101127 (3); Harlingen, AMNH 62118, UMMZ 105200-205, 105206 (5), 105207 (4). _Hidalgo Co._: Bentsen-Rio Grande State Park, UMMZ 114378; 6 mi. S McAllen, TNHC 7136-39; Santa Ana Refuge, TCWC 13495-96; Weslaco, TCWC 17658-60. MEXICO, _Nuevo Leon_: Salto Cola de Caballo, AMNH 57953-54, FMNH 30644-45, 37169-70; Monterrey, UIMNH 13324; 40 km. SE Monterrey, UIMNH 3686. _Tamaulipas_: 80 km. Matamoros, FMNH 27150 (13). Intergrades [_S. c. cystignathoides_ x _S. c. campi_ (88)] MEXICO, _San Luis Potosi_: 5 km. E Ciudad del Maiz, UMMZ 106435; 16 km. W Naranjo, FMNH 104584; Salto de Agua, 34 km. WSW Antigua Morelos, TCWC 6980. _Tamaulipas_: 5 km. W Acuna, 1060 m., UMMZ 101172, 101173 (16), 101174-76, 101177 (6); 14.5 km. NNW Chamal, 430 m., UMMZ 111337 (2); 20 km. NNW Chamal, 700 m., UMMZ 111338 (11); 8 km. N Gomez Farias, 450 m., UMMZ 101165; 8 km. NE Gomez Farias, Pano Ayuctle, UMMZ 102264, 102924 (6); 8 km. NW Gomez Farias, 1060 m., LSUMZ 11084, UMMZ 101199, 102928 (5), 102929-32, 110124 (3); Rio Guayala, near Magiscatzin, MCZ 24138-42, 85071-81, UMMZ 88242 (2); Magiscatzin, TCWC 6981; Las Yucas, north of Aldama, MCZ 29665-68; 16 km. NE Zamorina, UMMZ 101124. [Illustration: FIG. 4: _Syrrhophus cystignathoides campi_ (left, TCWC 13490) and _S. c. cystignathoides_ (right, KU 105500). Dorsal views x2, sides of heads x3.] =Syrrhophus cystignathoides cystignathoides= (Cope), New combination