  Loop operators of a class S theory arise from networks on the corresponding
Riemann surface, and their operator product expansions are given in terms of
the skein relations, that we describe in detail in the case of class S theories
of type A. As two applications, we explicitly determine networks corresponding
to dyonic loops of $N=4$ $SU(3)$ super Yang-Mills, and compute the
superconformal index of a nontrivial network operator of the $T_3$ theory.
