Lewis & Short

Ĭŏcasta (quadrisyl.), ae, and Ĭŏcastē, ēs, f., = Ἰοκάστη, the wife of Lāïus, and mother of Œdipus, whom she married unknowingly, and had by him Eteocles and Polynices.
Form Iocasta, Stat. Th. 1, 681; Hyg. Fab. 66.
Form Iocaste, Hyg. Fab. 67; 242.