Jamie is one of Lila's old friends, and Fatso is his "partner in crime." Lila deliberately seeks Jamie out when she and Phaedrus dock in Manhattan. She believes it will be a good idea for Phaedrus to have a second crew member aboard, though Phaedrus is reluctant. Upon meeting Jamie and Fatso, Phaedrus knows it is a bad idea and will never work. He can tell immediately that Jamie and Fatso are crooked opportunists who will do nothing but take advantage every chance they are given. They are equally disenchanted by Phaedrus whom they perceive as cold and calculating. It becomes clear that Fatso and Jamie acted as pimps to Lila at some point during her past. In regards to the role these two characters play in this work, it seems that Pirsig inserted them for a few different reasons. First, they give us some idea about Lila's past—what kind of people she associated with and what kind of life she led. Secondly, they represent "city morals."
Lila: An Inquiry Into Morals