For a curve C, viewed as a cycle in its Jacobian, we study its image n_*C
under multiplication by n on JC. We prove that the subgroup generated by these
cycles, in the Chow group modulo algebraic equivalence, has rank at most d-1,
where d is the gonality of C. We also discuss some general facts on the action
of n_* on the Chow groups.Comment: 18 pages, Latex 2.0
