  Distribution of the electron scattering rate on the Fermi surface of a
quasi-one-dimensional conductor is calculated for the electron-electron umklapp
interaction. We find that in certain regions on the Fermi surface the
scattering rate is anomalously high. The reason for the existence of these
``hot spots'' is analogous to the appearance of the van Hove singularities in
the density of states. We employ a generalized $\tau$-approximation (where the
scattering integral in the Boltzmann equation is replaced by the scattering
time which depends on the position at the Fermi surface) to study the
dependence of the electric resistance on the amplitude and the orientation of a
magnetic field. We find that the ``hot spots'' do not produce a considerable
magnetoresistance or commensurability effects at the so-called ``magic
angles''.
