The headword, presumably generated by the quotation given, is the nominative/accusative plural of a neuter noun meleagrion, which perhaps originated as a misinterpretation of me/li a)/grion "wild honey" eaten by John the Baptist (Matthew 3.4).
[1] Evidently an ascetic entertaining guests with food from wild plants. Quotation attributed to Symeon Metaphrastes by Adler, who notes that Angelo Mai (1782-1854) adduced PG 115.932a. See also mu 443 (Cyril?). Alternatively, in the TLG, see Menologii Imperiales Hagiogr., Fragmentum vitae deperditae sancti Euthymii 38.4; St. Euthymius' diet of wild foods is mentioned also at mu 117.
[2] Or melagria (mu 443).