Occasional Papers of the Museum of Zoology 3 



Masticophis ruthveni, new species 



Diagnosis : Characters very similar to those of Masticophis 

 schotti (B. & G.) from which it differs primarily in possessing 

 no dark lateral stripes. 



Range: Known only from Tamaulipas, Mexico, and ex- 

 treme southeastern Texas. 



Type Specimen: Cat. no. 57681, Aluseum of Zoology, Uni- 

 versity of ]\Iichigan. Brownsville, Texas. 



Description of Type Specimen: Scales in 15 rows anterior- 

 ly, reduced to 13, then to 12, and finally on the posterior por- 

 tion of the body to 1 1 ; reductions as follows: 15-13 by loss 

 of fifth row on each side of the body between scutes 111-113; 

 13-12 by loss of dorsal row above scute 131; 12-11 by loss 

 of dorsal row above scute 142. Ventrals 193, anal divided; 

 caudals 138 pairs; supralabials 8, the fifth extending up be- 

 hind the eye ; inf ralabials 9 ; oculars 2-2 ; temporals, right, 

 2 -|- 3 + 4. left, 2 -J- 3 -f 3 ; anterior chin shields in contact, 

 shorter and wider than posterior, the latter separated by 4 

 small scales ; loreal long and narrow ; nasals 2, nearly equal in 

 size, the nostrils ])etween them ; cephalic plates very similar 

 to those of M. schotti. 



Body slender and elongate, total length 16S cms.; tail 

 length 52 cms. ; proportionate tail length 0.310; sex male ; head 

 long and narrow, length 42 mm., width 19 mm., proportionate 

 width 0.45. 



The color and pattern are included in the general descrip- 

 tion of the form, which follows. 



Remarks: This new si>ecies is very rare in collections, but 

 it has been possible to study the coloration in a good series of 



