  The perturbative QCD approach to multiparticle production predicts a
characteristic suppression of particle multiplicity in a heavy quark jet as
compared to a light quark jet. In the Modified Leading Logarithmic
Approximation (MLLA) the multiplicity difference \delta_{Q\ell} between heavy
and light quark jets is derived in terms of a few other experimentally measured
quantities. The earlier prediction for b-quarks needs revision in the light of
new experimental results and the improvement in the understanding of the
experimental data. We now find \delta_{b\ell}=4.4\pm0.4. The updated MLLA
results on \delta_{b\ell} and \delta_{c\ell} are compared with the present data
from e^+e^- annihilation. Their expected energy independence is confirmed
within the energy range between 29 and 200 GeV; the absolute values are now in
better agreement with experiment than in the previous analysis, and the
remaining difference can be attributed largely to next-to-MLLA contributions,
an important subset of which are identified and evaluated.
