Pg. 754 of David Markson’s copy of The Complete Greek Drama: Volume One by Various (Ed. Whitney J. Oates & Eugene O’Neill, Jr.):

     On which Markson underlined three passages in Euripides’ Medea, just after the titular character has slain her children offstage:
     1) “Thy sons are dead; slain by their own mother’s hand.”
     2) “MEDEA appears above the house, on a chariot drawn by dragons; the children’s corpses are beside her.”
     (This also gets an angular bracket marking in the margins.)
     3) “Having borne me sons to glut thy passion’s lust, thou now hast slain them.”
     (This also gets an X in the margins.)

—

     The scene of Medea murdering her sons is not shown, interestingly enough.

     In fact:
     “Not one of the violent moments in Greek tragedy occurs on stage. Medea murdering her sons, for instance. Or Orestes bloodying Clytemnestra.”
     Wrote Markson on pg. 70 of Reader’s Block.