Long body & laterally flattened, smooth-scaled. Head distinctly broader than neck; large eye has vertical pupil. Two main colour forms, i.e. Red & black. In each form, the body pattern varies considerably: (i) uniform reddish-brown back with dull yellow markings; (ii) greyish-brown, brown or black blotches or bands that are interspersed with white patches.Hind-body has checkered pattern of same colours. Overall coloration can be very pale to very dark. In all colour forms, top of head has a dark mid-stripe, bounded on the neck by two additional marks.