OrHIBOLUS. 83 



long, narrowing on the sides as tlie white spaces enlarge, until on the 

 outer dorsal rows it occupies them to four scales, and is continued to 

 the middle of the abdomen ; owing to a slight obliquity of the dark 

 patches on the back, their abdominal extensions are very apt to 

 alternate with each other on the middle of the abdomen, instead of 

 being directly opposite and confluent. Every transition from the one 

 condition to the other is observable. The general pattern is thus : a 

 black body, encircled by white rings, which are wider on the sides 

 and beneath. The end of the tail is distinctly annulated. Occa- 

 sionally some of the black scales on the sides have indistinct white 

 spots in the centres. Labials, plates on the sides of the head, and 

 above in front of the vertical, yellow, with black margins. 

 El Dorado Co., Col. 240.52.23. 28. 3 i-. Dr. C. C. Boyle. 



2. Os»IiibolfiiS spIeildidMS, B. & G. — Black above ; the sides black, 

 with a white spot in each scale. The body crossed by broad bands, consist- 

 ing of white spots, one in each scale. Dorsal rows 23. 



Similar in general features to 0. Boylll. Vertical plate similar to 

 that of 0. Boyl'd but broader, and the sides more nearly parallel. 



This species forms a connecting link, as to color, between the 

 blotched varieties of 0. Sayl and 0. (jrtidus. There is a series 

 of dorsal black blotches from head to tail; in one specimen 63, 

 the 49th opposite the anus; in the other 52, the 41st opposite 

 the anus. These are four or five scales long, and six or seven wide. 

 The lighter intervals between are constituted by one or two trans- 

 verse rows of spots, each one on a separate scale. The scales on the 

 sides (from the 1st to the 7th or 8th rows) are black, each one with an 

 elongated white blotch in the centre. These blotches occupy nearly 

 the whole scale on the exterior row, but diminish in amount towards 

 the back. A series of rhomboidal darker spots is seen on each side 

 opposite the light intervals, produced by the less amount of white 

 on the scales at that place, and sometimes extend to the abdomen. 

 The abdomen is white, blotched not very deeply with black two or 

 three scales wide, and a continuation of the dark shade in the pro- 

 longation of the lateral rhomboids. The blotches of the opposite 

 sides are sometimes confluent and sometimes alternate. In one spe- 

 cimen the black patches are rather wider, extending nearly to the 

 abdomen. Head less blotched with yellow than 0. BoijUi. Dificrs 



