Sahih Muslim Book 007, Hadith Number 3097.
Chapter : Travelling of a woman with her Mahram for Hajj, etc.
This Hadith has been narrated on the same authority by Ubaidullah. And in the narration of Abu Bakr (the words are): "More than three (days)." Ibn Numair narrated on the authority of his father, (and the words are): "Three (days) except (when) she has a Mahram with her."