densityplot.
panel.densityplot(x, darg, plot.points = "jitter", ref = FALSE, groups = NULL, weights = NULL, jitter.amount, type, ..., identifier = "density")density
    function. Typically, this should be a list with zero or more of the
    following components : bw, adjust, kernel,
    window, width, give.Rkern, n,
    from, to, cut, na.rm (see
    density for details)
  "rug", in which case panel.rug is used to plot
    a rug, and "jitter", in which case the points are
    jittered vertically to better distinguish overlapping points.
  panel.superpose will be used instead to display each
    subgroup ... part must
    also include a subscripts argument that matches the weights
    to x.  plot.points="jitter", the value to use as the
    amount argument to jitter.
  type argument used to plot points, if requested.
    This is not expected to be useful, it is available mostly to protect
    a type argument, if specified, from affecting the density
    curve.
  panel.rug cannot be passed on through
    panel.densityplot. densityplot,
  jitter