The headword verb is the imperfect third person dual of ἡγέομαι , (see eta 51) glossed by the same verb in the plural form.
Ἡγείσθην is an Homeric reference occurring twice in this poet: Homer, Iliad 2.731 (web address 1) and Odyssey 14.470. All other occurrences in other writers are quotations or glosses of these verses.
The original source of the entry is the scholion to Homer, Iliad 2.731 (ἡγείσθην: ἡγοῦντο ), which came to the Suda through the Lexicon Ambrosianum. Indeed, in Laurentianus 59.16 folium 187r we have it identical to the Homeric scholion.