Locusta

• a woman famous for her skill in poisons, in the time of Nero and Claudius, Tac. A. 12, 66; 13, 15; Suet. Ner. 33; Juv. 1, 71.

• name of a man, Cic. Q. Fr. 3, 1, 2, § 4.

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]

or more correctly, Lucusta. A famous female poisoner, employed by Agrippina in poisoning the emperor Claudius, and by Nero for dispatching Britannicus. She was put to death in the reign of Galba (Tac. Ann. xii. 66; xiii. 15).