The first upper labial is not fused to the nasal and is completely separated by a suture.

There are 7-10 upper labials, the second of which is usually fused to the scale bordering the facial sensory pit anteriorly.

The fourth and fifth upper labials are beneath the eye, but separated from orbit by a series of 2-4 small scales.

The dorsal scales are smooth or weakly keeled, in 23-25, occasionally in 19 or 21 longitudinal rows at midbody.

Found in Asia in Nepal, India (Assam, Sikkim, Mizoram, Nagaland), Bangladesh[10] (already stated on the subspecies table), Myanmar, China (Zhejiang, Fujian, Sichuan, Yunnan, Tibet), Cambodia, Thailand, Laos, Vietnam, West Malaysia and Indonesia (Sumatra).