In this form only here, in the equivalent entry in ps.-Zonaras, and (according to Adler) in the Ambrosian Lexicon. Elsewhere Agarenoi: see e.g. Psalm 82:7 LXX ('Hagarenes'), I Chron. 5:19-20 ('Hagarites').
Dr Nick Nicholas suggests that the identification should rather be with the people of Agyrium (Ἀγυριναῖοι ) in Diodorus Siculus 4.24, 4.80, 14.78, 14.95, 16.82, 16.83, 22.2, 22.13, as this ethnic would be homophonous with the headword.