[3] C. helena is found in Sri Lanka, southern India, Pakistan (Shangla), Nepal, and Bangladesh.

[4] The dorsal scales are in 23 to 27 rows at midbody, smooth, or feebly keeled on the posterior part of the body and on the tail.

The adults are darker brown, with a transverse series of squarish black spots, or with more or less distinct traces of the color pattern of the young.

Some specimens have a white, black-edged collar; others have two black longitudinal streaks on the head; and others are intermediate in this respect.

The lower parts are yellowish, with or without a few small black spots, sometimes with a more or less distinct festooned marking on each side.

The preferred natural habitat of C. helena is forest, at altitudes from sea level to 2,500 m (8,200 ft), but it also found around houses.