  Structure of bifurcation diagram in the plane of parameters controlling
period-doublings for the system of coupled logistic maps is discussed. The
analysis is carried out by computing the charts of dynamical regimes and charts
of Lyapunov exponents giving showy and effective illustrations. The critical
point of codimension two at the border of chaos is found. It is a terminal
point for the Feigenbaum critical line. The bifurcation analysis in the
vicinity of this point is presented.
