As noted under alpha 3040, metrical lengthening of the epic adjective a)pere/sios can produce two forms: a)perei/sios and, as here, a)peire/sios. (See LSJ entry at web address 1.) The present entry appears, likewise, under the headword a)peire/sia in Hesychius alpha5904 and elsewhere, under a)perei/sia in Apollonius' Homeric Lexicon and elsewhere. Either way, it is neuter plural, generated probably by the phrase a)perei/sia e(/dna in Homer, Iliad 16.168 = Odyssey 19.529. (Note also a)perei/si' a)/poina, eleven times in the Iliad.)