or, more correctly, LUCUSTA (see Heinrich, ad Juv. vol. ii. p. 62), a woman celebrated for her skill in concocting poisons. She was employed by Agrippina in poisoning the emperor Claudius, and by Nero for despatching Britannicus. (Tac. Ann. 12.66, 13.15; Suet. Nero 33; D. C. 60.34; Juv. 1.71, with Schol.) Suetonius says (Nero, 33) that the poison which she administered being too slow, Nero impatiently struck her with his own hand, and forced her to prepare a stronger draught in his presence, which killed Britannicus instantaneously. She was rewarded by Nero with ample estates; but under the emperor Galba she was executed with other malefactors of Nero's reign. (D. C. 64.3.)
[W.I]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890