Upper panel: contour plot showing the predicted local relation M_BH−M_{∗ ,B} between the BH mass and the classical bulge mass. The contours indicate the number of galaxies in a M_BH−M_{∗ ,B} bin, normalized to the total number at fixed M_{∗ ,B} as shown in the colour bar. We compare these values with the data reported in Kormendy & Ho (2013) for ellipticals (circles) and classical bulges (diamonds) in spiral galaxies. The dashed line in the contour plot shows the fit log M_BH/M_⊙ = 1.15 log  (M_{∗ .B}/M_⊙)−3.84, while the histograms on the top show the average value and the scatter Δlog M_BH of the distribution of log M_BH/M_⊙ in different bins of bulge stellar mass. Lower panel: each coloured path shows the time evolution of the BH mass M_BH(t) and bulge mass M_{∗ B}(t) contributed by all progenitors of a few selected final galaxies. The circles show the onset of an active AGN phase; their size corresponds to the Eddington ratio λ ≡ Ṁ_BH/Ṁ_Edd as shown in the legend.