Honorable Lucy Byng by John Hoppner (Frick collection - New York City, New York USA)
Her article in thepeerage is here.
Lady Lucy wears a dress without a distinct bodice over a frilly chemise complemented by a lightweight coat with a lace collar.
Keywords: Hoppner, Lucy Byng, Byng family, Bridgeman family, Countess, British, hat, strap, lace, bows, trapezoidal neckline, chemise, vee neckline, waist band, close skirt, coat, collar, necklace