How to Ask a Professor to be thesis referee
Hello Dr. Foo,
  
  My advisor, Dr. Bar, recommended that I should contact you to referee my thesis, "Underwater Basket Weaving." I was wondering if I could meet with you to provide you the thesis and answer any questions you may about it beforehand. Please let me know if you'd be interested and, if you are, the best time and location for me to meet you. Thank you for your time.
  
  Sincerely,
  
  Spongebob


Be polite, be clear, be accommodating. Your professor is unlikely to introduce you two because he probably doesn't want to appear as if he's using the potential referee as a resource rather than as a colleague. Furthermore, interacting with people you don't know through e-mail and real life is commonplace in academia, so it stands to reason your supervisor would want you to try it out.