  The statistics of gravitationally lensed arcs, which can be used for a
variety of cosmological tests, are sensitive to the intrinsic shapes of the
source galaxies. I present an analytic formalism that makes it simple to
include elliptical sources in analytic calculations of lens statistics. For
cuspy lens models, sources with an axis ratio of 2:1 enhance the total number
of arcs longer than 10:1 by a factor of order two, while modestly decreasing
the number ratio of radial arcs to tangential arcs. Source ellipticity is
therefore an important systematic effect in detailed quantitative studies, but
it should not hinder cosmological applications such as attempts to constrain
cluster dark matter profiles with arc statistics.
