  In a recent article [10], the authors proved that the non-relativistic
Schr\"odinger operator with a generic honeycomb lattice potential has conical
(Dirac) points in its dispersion surfaces. These conical points occur for
quasi-momenta, which are located at the vertices of the Brillouin zone, a
regular hexagon. In this paper, we study the time-evolution of wave-packets,
which are spectrally concentrated near such conical points. We prove that the
large, but finite, time dynamics is governed by the two-dimensional Dirac
equations.
