  Optical spectroscopy was used to investigate the optical gap (2$\Delta $) due
to charge ordering (CO) and related pseudogap developments with x and
temperature (T) in La$_{1-x}$Ca$_{x}$MnO$_{3}$ (0.48 <= x <= 0.67).
Surprisingly, we found 2$\Delta $/k_{B}T_{CO} is as large as 30 for x ~0.5, and
decreases rapidly with increasing x. Simultaneously, the optical pseudogap,
possibly starting from T^* far above T_{CO} becomes drastically enhanced near
x=0.5, producing non-BCS T-dependence of 2$\Delta $ with the large magnitude
far above T_{CO}, and systematic increase of T^* for x~0.5. These results
unequivocally indicate systematically-enhanced CO correlation when x approaches
0.5 even though T_{CO} decreases.
