Pray ye for me (Deēthēte humeis huper emou). Emphasis on humeis (you). First aorist passive imperative. Simon is thoroughly frightened by Peter’s words, but shows no sign of personal repentance or change of heart. He wants to escape the penalty for his sin and hopes that Peter can avert it. Peter had clearly diagnosed his case. He was an unconverted man in spite of his profession of faith and baptism. There is no evidence that he ever changed his life at all.
Which (hōn). Genitive by attraction of the accusative relative ha to case of the unexpressed antecedent toutōn (of those things), a common Greek idiom.