  In this paper we study the bifurcations of a class of polycycles, called
lips, occurring in generic three-parameter smooth families of vector fields on
a M\"obius band. The lips consists of a set of polycycles formed by two
saddle-nodes, one attracting and the other repelling, connected by the
hyperbolic separatrices of the saddle-nodes and by orbits interior to both
nodal sectors. We determine, under certain genericity hypotheses, the maximum
number of limits cycles that may bifurcate from a graphic belonging to the lips
and we describe its bifurcation diagram.
