(Πελασγίς), or PELASGIS, i. e. the Pelasgian (woman or goddess), occurs as a surname of the Thessalian Hera (Apollon. 1.14, with the Schol.; Propert. 2.28. 11), and of Demeter, who, under this name, had a temple at Argos, and was believed to have derived the surname from Pelasgus, the son of Triopas, who had founded her sanctuary. (Paus. 2.22.2.)
[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