  We report calculations of oscillator strengths for the far infrared
absorption of light by the excitonic complexes Xn- (the excess charge, n,
ranging from one to four) confined in quantum dots. The magnetic field is
varied in an interval which corresponds to ``filling factors'' between 2 and
3/5. Electron-hole interaction effects are seen in the deviations of the peak
positions from the Kohn lines, and in the spreading of the oscillator strengths
over a few final states. Transition densities are used as an additional tool to
characterize the absorption peaks.
