Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Ărĭadna, ae (nom. Ariadna, Cat. 64, 54; Prop. 2, 3, 18; Ov. A. A. 3, 35: Ariadne, Hyg. Fab. 255; 270: gen. ARIADNES, Corp. Inscr. 5, 3782: acc. Ariadnen, Hyg. Fab. 43; 224: abl. Ariadne, id. ib. 42), f., = Ἀριάδνη, daughter of Minos, king of Crete, who extricated Theseus from the Labyrinth, and accompanied him on his return to Greece, but was deserted by him at Naxos, where Bacchus fell in love with her and placed her crown as a constellation in the heavens, Ov. A. A. 3, 35 (cf. id. H. 10); id. F. 3, 462; Prop. 3, 17, 8; 2, 3, 18.
Also in prose, Mel. 2, 7, 12.
Hence, Ărĭadnae-us, a, um, adj., = Ἀριαδναῖος, of or pertaining to Ariadne, Ariadnœan: sidus, Ov. F. 5, 346: corona, Manil. 5, 21.