Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† hydraula, ae, or hydraules, ae, m., = ὑδραύλης, one who plays on the waterorgan, Suet. Ner. 54; Petr. 36; acc. -am, Mart. Cap. 9, § 924.
† hydraulus, i, m., = ὕδραυλος, a water-organ, Cic. Tusc. 3, 18, 43; Plin. 9, 8, 8, § 24.