By definition, hermatia is a tragic flaw that leads to the downfall of a hero or heroine. 

According to Aristotle, the protagonist of a tragedy will bring about his own downfall not because of moral sin, but because he or she does not know enough. Oedipus fits this precisely, for his basic flaw is his lack of knowledge about his own identity. In lines 819-822, Oedipus even states his flaws saying, “And it is I, and no other have so cursed myself. And I pollute the bed of him I killed by the hands that killed him. Was I not born evil?”  Here Oedipus resents his great mistake of killing his father and marrying his own mother. Just as Aristotle states, Oedipus does not understand his identity and made a very bad judgment call. This judgment or error is his hermatia. 

Aside from not understanding his identity, Oedipus is very prideful, and his pride blinds him.  An example of his pride is found in lines 269-271 when Oedipus says, “Those who do not obey me, may the Gods grant no crops springing from the ground they plough nor children to their women!”(Greek Tragedies 121). Here, Oedipus thinks that he should be worshipped, and those that do not worship and obey him should be destroyed. When Oedipus is talking to the Chorus he also says that he can grant their prayers instead of the Gods.  Oedipus believes he is even more powerful than the Gods, and his pride eventually blinds him. When Oedipus saves the people of Thebes by killing the Sphinx, he feels confident and prideful in his actions. By defeating the Sphinx, he gains an unrealistic sense of power and only wants to be greater. The irony in this situation is that his greatness is cut down by his tragic flaw or hermatia.  

Overall, Oedipus cannot see his own negative flaws because he is too prideful.  He becomes so focused on himself and his glory, that he does not realize hisfoolish mistake of killing his father and marrying his mother.  Therefore, the hermatia of Oedipus lies in his inability to see his real identity. In the end, Oedipus wanders around blindly because he was too prideful and made mistakes.