What metaphors are used in Electra by Hugo von Hofmannsthal?

Hofmannsthal's claustrophobic spaces are generally metaphors of the womb. The cave is the favored image. In Oedipus and the Sphinx, the oracle warning Laius against a son takes this form....

Let the king be on his guard and stand at his wife's bed armed and with a naked sword as if at the cave from which his worst enemy is lurking to burst forth.