E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
in the Legislative Assemblies, is a person employed to whip up members on either side. The Whips give notice to members that a motion is expected when their individual vote may be desirable. The circular runs: A motion is expected when your vote is earnestly required. If the word earnestly has only one red-ink dash under it the receiver is expected to come, if it has two dashes it means that he ought to come, if it has three dashes it means that he must come, if four dashes it means stay away at your peril. These notices are technically called RED WHIPS. (Annual Register, 1877, p. 86.)
A whip. A notice sent to a member of Parliament by a whip (see above) to be in his place at the time stated when a division is expected.