8 University of Michigan 



on the red scales, and (c) by a light-colored snout mottled with 

 darker. 



While this color pattern seems to be constant on the west coast, 

 it is very noticeable that toward the interior of Mexico some 

 specimens have the spaces on the belly opposite the dorsal red 

 areas partially or completely filled with black, presenting in this a 

 striking approach to L. triangulum annidata (Kennicott). The 

 snout, too, may be blacker, and the red interspaces between the 

 pairs of black rings may be much narrower and strongly encroached 

 upon by the latter. 



Since in structural features this form is very close to L. tri- 

 angulum annidata, it is believed that these similarities in pattern 

 toward the interior of Mexico are sufficient evidence of inter- 

 gradation with the latter. 



Lampropeltis ruthveni, new species 

 Plate I, Figure 2 



Diagnosis: A ringed form similar in coloration to L. polyzona 

 Cope, L. triangulum nelsoni Blanchard, and L. multicincta (Yarrow). 

 From L. polyzona it differs in the complete absence of black tips 

 on the red and whitish scales, in the completely black head, and 

 in the low number of ventral plates, 189. From L. triangulum 

 nelsoni it differs principally in the higher nimiber of annuli, 30, and 

 the much narrower red rings, two to three scales in width. From 

 L. multicincta it is distinguished by the low numbers of ventrals 

 and annuli, by the fact that the black rings show scant, if any, 

 tendency to overspread the red areas dorsally, and by the mottling 

 of the yellow rings with darker, particularly on the sides. 



Range: Patzcuaro, Michoacan, Mexico. 



Type Specimen: United States National Museum No. 46558 

 (skin and head only) ; Patzcuaro, Michoacan, Mexico; collected by 

 E. W. Nelson, August 2, 1892. 



