Parthax wrote Italica. Herodian quotes book 2: Heracles came to Poseidonia, where a great river is called Is. The Great Etymologicon adds that the same stream was later Cyllistanos, because Heracles killed a huge snake there and it rolled into the water. Eustathius on Iliad 734.48 records that Parthax called Caulonia Aulonia.
Karl Müller printed the notices in Fragments of the Greek Historians 4. Parthax is dated after the second century CE.
The fragments preserve Italic geography: a river at Poseidonia, a Heracles aetiology, and a south-Italian toponym.
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