Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Alcmēna or Alcŭmēna, ae, also Alcmēnē, ēs, f. (always Alcumena in Plaut. Am.: Alcmene, Ov. M. 9, 276; gen., Gr. Dor. Alcumenās, Plaut. Am. Argum.; Alcmenes, Sen. Herc. Oet. 1825), = Ἀλκμήνη, daughter of Electryon, wife of Amphitryo, and mother of Hercules by Jupiter, and of his twin-brother Iphiclus by Amphitryo, Plaut. Am.; Hyg. Fab. 29 al.