Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Hērāclĕŏpŏlis, is, f., = Ἡρακλέους πόλις, a city of Egypt upon an ancient island of the Nile, which has become part of its western bank, now Ahnas, Mart. Cap. 6, § 676.
Hence, Hērāclĕŏpŏlītes, ae, adj., of Heracleopolis: nomos, Plin. 36, 13, 19, § 84.
Plur. subst.: Hērāclĕŏpŏlī-tae, ārum, m., the inhabitants of Heracleopolis, Plin. 36, 13, 19, § 86.