For the neuter headword, here in the plural (probably quoted from Aristophanes), see generally LSJ s.v., which notes a primary sense of 'bogey, hobgoblin' besides the one illusrated here.
[1] For gorgia see gamma 389. This material also occurs in other lexica (see the references at Photius mu530 Theodoridis), and various scholia (notably to Plato, Axiochus 364B).
[2] Theophylact Simocatta, Histories 6.5.7, on the abrupt withdrawal of the Avars (cf. alpha 18 generally) from the field of battle at Drizipera (cf. delta 1528) in 593; cf. de Boor (228) and Whitby (165). Theophylact attributes their flight to the Avars having suffered from the delusion of an immense Roman force advancing upon them. The Whitbys more plausibly suggest (165 note 27) that the Avar khan withdrew in order to confront Priscus. On Priscus, see PLRE IIIb s.v. Priscus(6).