White caps

Related to White caps: Canucks
the members of a secret organization in various of the United States, who attempt to drive away or reform obnoxious persons by lynch-law methods. They appear masked in white. Their actions resembled those of the Ku Klux Klan in some ways but they were not formally affiliated with the Klan, and their victims were often not black.

See also: White

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in classic literature ?
Then they crept up alongside of the dock and the sailors threw the quivering fish over the side of the boat; a line of carts was waiting for them, and women with white caps sprang forward to receive the baskets and embrace their men-folk.
Nine-tenths of the Heidelberg students wore no badge or uniform; the other tenth wore caps of various colors, and belonged to social organizations called "corps." There were five corps, each with a color of its own; there were white caps, blue caps, and red, yellow, and green ones.
A strong cheerful peasant woman, all stocking, petticoat, white cap, and ear-ring, stood here in a dark doorway, and said with a pleasant show of teeth, 'Ice-say!
Raoul had been there about ten minutes, during five of which he was lost in reverie, when there appeared within the circle comprised in his rolling gaze a man with a rubicund face, who, with a napkin around his body, another under his arm, and a white cap upon his head, approached him, holding paper, pen and ink in hand.
The little princess lay supported by pillows, with a white cap on her head (the pains had just left her).
He was immediately followed by a heavy red-haired man in a white cap. At the sight of the former the staghounds, who had all tired of barking at me by this time, became furiously excited, howling and leaping against their chains.
I had thought to see a tall, meagre, yellow, conventual image in black, with a close white cap, bandaged under the chin like a nun's head-gear; whereas, there stood by me a little and roundly formed woman, who might indeed be older than I, but was still young; she could not, I thought, be more than six or seven and twenty; she was as fair as a fair Englishwoman; she had no cap; her hair was nut-brown, and she wore it in curls; pretty her features were not, nor very soft, nor very regular, but neither were they in any degree plain, and I already saw cause to deem them expressive.
In the coach was an old lady dozing in one corner, and at the window, evidently only just awake, sat a young girl holding in both hands the ribbons of a white cap. With a face full of light and thought, full of a subtle, complex inner life, that was remote from Levin, she was gazing beyond him at the glow of the sunrise.
When Tess had occupied herself about an hour the next morning in altering and improving the arrangements, according to her skilled ideas as the daughter of a professed poulterer, the door in the wall opened and a servant in white cap and apron entered.
She wore a black woollen dress, with a black handkerchief round her neck and shoulders, and a white cap with black ribbons.
Girdlestone; ordered for all the servants, under the admiral's instructions -- a white muslin apron, and a neat white cap and collar, with ribbons to match the gown.
She wore a black wig under a white cap. Her swollen legs rendered her inactive.