REPTILES AND AMPHIBIANS OP TEXAS 41 



in every respect with the type, I shall here recognize 

 it as a distinct species. 



125. Heterodon platyehinus Latreille. Spreading Adder: 



Hog-nosed Snake. 

 The "blowing adder" is distributed over the entire 

 eastern and middle sections west to the foot of the 

 plains and south almost to the Rio Grande River. 

 This species follows the canyons in the Panhandle 

 and by this means penetrates the plains region for a 

 short distance. 



126. Heterodon nascius Baird and Girard. Western 



Spreading Adder. 

 Western Texas, extending eastward in the Rio 

 Grande Valley as far as Cameron County. Common 

 in the trans-Pecos counties and in the Panhandle 

 west of the foot of the plains. In the Rio Grande 

 Valley this species seems to be found only in the 

 border counties and does not range northward into 

 the interior for any distance. 



127. SiBON SEPTENTRIONALIS Kennicott. Ringed Snake. 



This and the following species are tropical snakes 

 which extend their range into North America only in 

 the extreme southern portion of Cameron County, 

 Texas. Sibon septentrionalis has been captured at 

 Brownsville on several occasions. 



128. Erythrolamprus imperialis Baird. Imperial Snake. 



Brownsville, Texas. 



129. Tantilla nigriceps Kennicott. Black-headed Tantilla. 



Western and Southern Texas. Recorded from San 

 Antonio and San Diego by Cope and from Pecos by 

 Brown. Cope says that it is common between the 

 upper waters of the Brazos and Colorado Rivers. I 

 did not find it in any of the localities visited by me. 



130. Tantilla gracilis Baird and Girard. Graceful Tan- 



tilla. 

 Texas, we§t to the foot of the plains, south to the 



