The Collaborative International Dictionary
harlequin snake \har"le*quin snake`\ n. any of several venomous New World snakes brilliantly banded in red and black and either yellow or white, especially the eastern coral snake, a small poisonous snake ( Micrurus fulvius or Elaps fulvius), ringed with red and black, found in the Southeastern United States. They are widely distributed in Southern and Central America;
Syn: coral snake, New World coral snake.
Micrurus \Micrurus\ prop. n. A genus of snakes including certain of the coral snakes, such as the eastern coral snake ( Micrurus fulvius).
Syn: genus Micrurus.
Wikipedia
Micrurus fulvius (Eastern coral snake, common coral snake, American cobra, more) is a species of venomous elapid snake endemic to the southeastern United States. It should not be confused with the scarlet snake (Cemophora coccinea) or scarlet kingsnake (Lampropeltis elapsoides), which are harmless mimics. No subspecies are currently recognized.