open-kneed breeches

1719, William Mountfort, Greenwich-Park; A Comedy, London: G. Strahan & W. Mears, Act I, Scene 1, If the Times are alter’d with the Wives, so they are with the Husbands, since they wore slash Doublets, short Cloaks, and open knee’d Breeches, with their own thin lank Hair, that look’d liek the Fringe of a Blanket, or the Strings of a Bunch of Leeks; you can now wear the best Fashion and richest Cloaths, Swords upon Occasion […]

1782, Gentleman’s Magazine, September, 1782, Letter signed ‘A.B.,’ p. 434, There is a remarkable painting of a galante of the time of Edward IV, in the Hungerford chapel in the cathedral of Salisbury […] in which the hose is continued from the shoe to the waist without any sign of gartering at the knee, all of one piece. In the mutability of garbs, which continued to the reign of James I, slops, which may be considered as open-kneed breeches, soon followed.

1835, Charles Joseph Latrobe, The Rambler in North America: 1832-1833, London: R.B. Seeley et al., Volume 2, Letter 12, p. 222, Here comes a ship load of Irish. They land upon the wharfs of New York in rags and open-knee’d breeches, with their raw looks and bare necks; they flourish their cudgels, throw up their torn hats and cry,—‘hurrah for Gineral Jackson!’