Conventionally, the headword phrase is Aristophanes fr. 381 Kock, now 396 Kassel-Austin. However, in her critical apparatus Adler deems this rash ('temere') and points instead (following Dindorf) to Ecclesiazusae 667: see n. 2 below. If that is correct, the present lemma has supplied the negative. Alternatively this is an adaptation of the quotation given (see n. 3 below, where the adjective/pronoun au)to/s (same, self) is not masculine (or neuter) dative singular but plural. Either way, the verb form here is the present active participle, neuter nominative, accusative, and vocative (and masculine vocative) singular form of the verb me/teimi, I am among, have a share in; see generally LSJ s.v.
[1] The participle in the gloss is the same form as in the headword phrase, but from the verb e)/cesti, it is allowed, in one's power, possible; see generally LSJ s.v.
[2] As noted above, the correct location for the lemma is probably Aristophanes, Ecclesiazusae [Assemblywomen] 667 (web address 1), where Praxagora rhetorically asks her husband Blepyrus, pw=s ga\r kle/yei meto\n au)tw=|;, For how can someone steal what he has a share in?. [In her critical apparatus Adler notes that the phrase 'Aristophanes in Clouds', lacking in ms F, was attractively related by Bernhardy to omicron 919.]
[3] The quotation was attributed to Menander Comicus by Kock (as his fr. 901). Adler castigated this as false, assigning it instead (albeit without a specific reference) to the historian Menander Protector (C6 CE). Possibly, then, the passage pertains to the restoration of the water supply for the city of Daras (Dara, Anastasioupolis; Barrington Atlas map 89 grid C3; about 20km southeast of modern Mardin, Turkey; cf. alpha 3174, delta 68, and delta 1009) by Ioannes (John, son of Domnentiolus; d. 567; no. 81 in PLRE IIIa, pp. 672-4) while on a diplomatic mission in 567 from Emperor Justin II (Eastern Emperor 565-78 CE; PLRE IIIa, s.v. Iustinus 5, pp. 754-6); cf. Blockley, pp. 96-9. However, attribution to Menander the comic poet has persisted: fr. 802 Koerte-Thiefelder, and latterly fr. 885 Kassel-Austin.