The species is endemic to the rain forests and grasslands of Sri Lanka.

[1] The specific name, blythii, is in honor of English zoologist Edward Blyth (1810-1873), curator of the museum of the Asiatic Society of Bengal.

The sides have vertical yellow spots or a wavy or zigzag stripe on the anterior half of the body.

Adults may attain a total length (including tail) of 37 cm (14+1⁄2 in).

Some of the distal dorsal scales of the tail are weakly keeled.