Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Pĭthēcūsa, ae, and Pĭthēcūsae, ārum, f., = Πιθηκοῦσαι, an island (prop. the western and larger of two islands; whence the plur.) in the Tyrrhenian Sea, not far from Cumœ, the modern Ischia, Mel. 2, 7, 18; Plin. 3, 6, 12, § 82; Liv. 8, 22; Ov. M. 14, 90: Inarime a Graecis dicta Pithecusa, Mart. Cap. 6, § 644.