[2] P. nigromarginata is found in Bhutan, Nepal, India (Darjeeling, Sikkim, Assam, Nagaland), northern Bangladesh, northern Myanmar (= Burma), China (Guizhou, Yunnan, southwestern Sichuan, southeastern Xizang [= Tibet]), and possibly northern Vietnam.

[2] A large snake, P. nigromarginata may attain a total length of 2.26 m (7.4 ft), which includes a tail 0.65 m (2.1 ft) long.

In adults, there are four broad black stripes on the posterior third of the body and on the tail.

In juveniles the stripes extend the full length of the body and tail.

This article relating to Colubrinae is a stub.