(Ἀνδρεύς), a son of the river-god Peneius in Arcadia, from whom the district about Orchomenos in Boeotia was called Andreis. (Paus. 9.34.5.) In another passage (10.13.3) Pausanias speaks of Andreus (it is, however, uncertain whether he means the same man as the former) as the person who first colonized Andros. According to Diodorus (5.79) Andreus was one of the generals of Rhadamanthys, from whom he received the island afterwards called Andros as a present. Stephanus of Byzantium, Conon (41), and Ovid (Ov. Met. 14.639), call this first colonizer of Andros, Andrus and not Andreus.
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890