Striped whipsnake

It is of average size, not very thick. It is long; when mature it is four [or] three fathoms. It is yellow, chili-red, green, white, which run along its back; it is striped with them. It is not poisonous; only when it is made angry, or when it hunts, it just coils itself about one, crushes one, or chokes one. It is called hecacoatl because when it travels it raises itself erect. On level land, it goes standing on the end of its tail; it is as if it went flying along. And when it emerges on grasses, on bushes, when it goes there, it is as if a narrow current of air emerged.