326 Annals of the Carnegie Museum. 



Scales usually in nineteen to twenty-three rows, occasionally in 

 seventeen or twenty-five rows, the vertebrals sometimes slightly 

 enlarged; gastrosteges one hundred and sixty-four to two hundred and 

 eleven; anal divided; urosteges sixty-eight to one hundred and seven 



Yellowish above, with one or two rows of reddish brown spots, which 

 are often confluent into an undulating or zigzag band, or form cross- 

 bars; a lateral series of spots of extremely variable size, sometimes 

 scarcely visible; often a dark median line on the occiput; a dark 

 streak behind the eye; lower surface white, or occasionally with fine 

 brown dots; lower surface of tail frequently brownish. 



Habitat. — From Mexico to Argentina. 



