2 CROTALUS. ' 



the superciliaries. A series of three or four larger flat scales extends 

 fi'om the posterior extremity of the superciliary. Scales on the cheeks 

 very large, truncate. Anterior orbitals double; the upper one rect- 

 angular, elongated longitudinally ; separated from the nasal by two 

 small plates. 



General color above, that of roll sulphur; beneath, whitish yel- 

 low. Along tlie back is a double series of subrhomboidal blotches, 

 looking as if they had been in contact, and then the line of junction 

 partially effiiced for the three or four central rows. The impression 

 conveyed of the color of these blotches is that of coarse mottlings 

 of soot or gunpowder grains, more crowded exteriorly. There are 

 twenty-one of these blotches from the head to the anus, the tail being 

 entirely black. The rhomboids are enclosed within about twelve 

 dorsal series of scales. Directly opposite to these spots on each side 

 is a series of subtriangular blotches similarly constituted as to colour, 

 and extending from the abdomen to about the fifth lateral row, and 

 some six or seven scales long. Anteriorly these are distinct from the 

 dorsal series, but posteriorly they are confluent with them, forming a 

 series of zigzag blotches across the body. The scutellai below show 

 more or less of the grain-like mottlings. Posteriorly the yellow of 

 the body is suffused with darker. 



There are no markings of lines distinctly visible on the sides of 

 the head. In the centre of the spaces between the dorsal and lateral 

 series of blotches are indications of small obsolete spots ; and in some 

 cases the yellow scales external to the blotches are of lighter colour 

 than the rest. 



Huntingdon Co., Pa. 166. 25. 23. 42. 5. D. C Lloyd. 



Another specimen has the ground-color darker, more brownish 

 yellow. The markings, however, are on the same pattern, except 

 that the line of junction of the blotches is not so much effaced, and 

 the colors more decided. Lateral row of scales smooth, not cari- 

 ated Plates of head similar. Fifteen labial plates, fourth upper 

 one the largest. The blotches are nearly uniform umber-brown, 

 margined with darker ; the scales external to which are lighter than 

 the ground-color. 

 Lycoming Co., Pa. 165. 25. 23. 25. 3^. S. F. Baird. 



A female from Huntingdon Co., Pa., has the general pattern of 

 the one last mentioned, but a dark brown tint pervades the whole 



