Cope.] "^^^ [April 17, 



The most difficult problems to settle in the genus Sceloporus, are the 

 limits of the species S. torquatus and S. undulatus. With considerable 

 material, and the experience of Mr. Bocourt before me, I do not feel that 

 I can make more than a contribution to the question as regards the 8. tor- 

 quatus. The collection of individuals I include under that name, embraces 

 some with one row of large supraocular plates, and some with two ; some 

 with mucronate, and others with entire dorsal scales in numbers varying 

 from twenty-five to thirty-five between occiput and groin ; specimens with 

 the anterior collar border divided and those where it is entire ; and those 

 with blue and those with gray throat and chin. In the following synopsis 

 of varieties I indicate the localities where they are derived. 



I. One row of large supraocular scales. 



Dorsal scales not mucronate ; collar border not interrupted. .8. t. torquatus. 

 Xalapa, Keating. 



II. Two rows of large supraocular plates. 



Dorsal scales not mucronate ; collar border not interrupted ; nowhere 



blue. 8. t. poinsettii. 



(Four from S. W. Texas, Cope, and two from uncertain Mexican locali- 

 ties.) 



Dorsal scales not mucronate ; collar with anterior border divided ; back 

 dark spotted, sometimes with light borders ; chin, throat and sides 



blue S. t. cyanogenys. 



(Seven from Monterey, Nuevo Leon, Cope.) 

 Dorsal scales strongly mucronate ; anterior collar border divided, and 

 forming two yellow spots on nape ; sides blue ; chin and throat not 



blue 8. t. mucronatus. 



(Four from Vera Cruz, Sartorius.) 

 Dorsal scales stongly mucronate, a little smaller (eight equaling head) ; 

 collar very slightly interrupted, borders very pale ; green, sides and 

 narrow inferior collar blue ; chin and throat not . , . . . . *S'. ^. formosus. 

 Four from Xalapa, Monies de Oca. 



As in 8. t. cyanogenys, but scales smaller ; 8-10 in head ; smaller 



8. t. minor. 

 Two specimens from Duges ; Zacatecas. 



Finally the second form described under 8. melanogaster may constitute 

 another variety approaching the 8. t. torquatus, but with the anterior 

 collar border interrupted as in *Si. t. cyanogenys, and the back spotted as 

 in 8. t. formosus. 



Should the interruption of the collar seen in the 8. serrifer prove to be 

 an inconstant character, that form must be regarded as subordinate to the 

 8. torquatus, entering Sect. I, but related to the 8. t. mucronatus. Should 

 the anterior canthal scale appear in the 8. melanogaster, nothing but color 

 will distinguish it from the 8. t. torquatus, but the strongly mucronate 

 scales, and the very diflferent color, which are, however, weakened in 

 importance by the 8. t. mucronatus with similiar scales, and the 8. t. cyano- 

 genys with its blue chin and throat. 



