Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Perseus.
Pĕlŏpēa, Pĕlŏpēĭas, Pĕlŏpēis, Pĕlŏpēïus, Pĕlŏpēus, Pĕlŏpĭdae, v. Pelops.