  The Wigner delay time is addressed semiclassically using the Miller's
S-matrix expressed in terms of open orbits. This leads to a very appealing
expression, in terms of classical paths, for the energy averaged Wigner time
delay in chaotic scattering. The same approach also puts in evidence the
semiclassical incapability to correctly assess the time delay higher moments.
This limitation suggests that the use of the semiclassical approximation to
quantify fluctuations in scattering phenomena, like in mesoscopic physics, has
to be considered with great caution.
