  We describe a topological relationship between slices of the parameter space
of cubic maps. In the paper \cite{CP1}, Milnor defined the curves
$\mathcal{S}_n$ as the set of all cubic polynomials with a marked critical
point of period $p$. In this paper, we will describe a relationship between the
boundaries of the connectedness loci in the curves $\mathcal{S}_1$ and
$\mathcal{S}_2$.
