  As planetary embryos grow, gravitational stirring of planetesimals by embryos
strongly enhances random velocities of planetesimals and makes collisions
between planetesimals destructive. The resulting fragments are ground down by
successive collisions. Eventually the smallest fragments are removed by the
inward drift due to gas drag. Therefore, the collisional disruption depletes
the planetesimal disk and inhibits embryo growth. We provide analytical
formulae for the final masses of planetary embryos, taking into account
planetesimal depletion due to collisional disruption. Furthermore, we perform
the statistical simulations for embryo growth (which excellently reproduce
results of direct $N$-body simulations if disruption is neglected). These
analytical formulae are consistent with the outcome of our statistical
simulations. Our results indicate that the final embryo mass at several AU in
the minimum-mass solar nebula can reach about $\sim 0.1$ Earth mass within
$10^7$ years. This brings another difficulty in formation of gas giant planets,
which requires cores with $\sim 10$ Earth masses for gas accretion. However, if
the nebular disk is 10 times more massive than the minimum-mass solar nebula
and the initial planetesimal size is larger than 100 km, as suggested by some
models of planetesimal formation, the final embryo mass reaches about 10 Earth
masses at 3-4 AU. The enhancement of embryos' collisional cross sections by
their atmosphere could further increase their final mass to form gas giant
planets at 5-10 AU in the solar system.
