I feel I should point out that the mafia originated as a Sicilians only club. Not that the very same problems you mentioned didn’t drift over from the boot. Just thought it should be made clear it wasn’t until later that Italians proper were allowed in.
The grandfather of the Mafia was the Camorra, who are from the region of Naples. It predates the Sicilian Cosa Nostra by about a hundred years. What also confuses the issue is that some of these groups were at least partially like the secret patriotic revolutionary organizations, such as the Carbonari.
http://en.wikipedia.org/wiki/Camorra