Meaning of "coastal plain" milk snake

a harmless North American constrictor that is typically strongly marked with red and black on yellow or white. It was formerly supposed to suck milk from sleeping cows.

milk snake

milk snake
n.
Any of various subspecies of the king snake Lampropeltis triangulum, ranging from the eastern and central United States south to Ecuador and often having red, black, and yellow or white bands. Also called house snake, milk adder.

[From the folk belief that the snakes (which are commonly seen around the barns where they hunt rodents) suck milk from cows.]

milk snake

milk snake
n
(Animals) a nonvenomous brown-and-grey North American colubrid snake Lampropeltis doliata, related to the king snakes

milk′ snake`

milk′ snake` n.
any of numerous, usu. brightly marked king snakes of the subspecies Lampropeltis triangulum (doliata), of North America.
[1790–1800]