Does it? That's not how I read it, but I'm not a Constitutional Lawyer. Here's the full clause

"The Senators and Representatives shall receive a Compensation for their Services, to be ascertained by Law, and paid out of the Treasury of the United States. They shall in all Cases, except Treason, Felony and Breach of the Peace, be privileged from Arrest during their Attendance at the Session of their respective Houses, and in going to and returning from the same; and for any Speech or Debate in either House, they shall not be questioned in any other Place."

I guess the semicolon can be interpreted in two ways, although I interpret the Speech or Debate clause as being only after the semicolon; the use of "and for any..." also does not seem to exclude felonies. Logically the clause would also seem to lose any bite it might have if things the legislature declared a felony were then excluded from Speech or Debate. But again, IANACL.