Adult length 20-45 cm. A small, smooth-scaled snake, the body is the thickness of a pencil. The 15 rows of scales distributed around the dorsal part of the body range from reddish along the back to grey along the sides. Adults have an indistinct, dark lateral stripe that terminates in a dark line across each eye of the blunt nosed head. Belly scales are light grey to a greenish-blue with a sharp black bar lining each ventral scale (“scute”), giving the snake a characteristic black and white pattern on the ventral area. Juveniles are a distinctly solid brick-red with yellowish-brown lateral lines. On adults and juveniles the dorsal scales near the tail are uniformly red, terminating in a small sharp “spur” that divides the anal plate and from which the species derives its name.