  The rich oscillation spectra determined for the two stars, Nu Eridani and 12
Lacertae, present an interesting challenge to stellar modelling. The stars are
hybrid objects showing a number of modes at frequencies typical for Beta Cep
stars but also one mode at frequency typical for SPB stars. We construct
seismic models of these stars considering uncertainties in opacity and element
distribution. We also present estimate of the interior rotation rate and
address the matter of mode excitation.
  We use both the OP and OPAL opacity data and find significant difference in
the results. Uncertainty in these data remains a major obstacle in precise
modelling of the objects and, in particular, in estimating the overshooting
distance. We find evidence for significant rotation rate increase between
envelope and core in the two stars.
  Instability of low-frequency g-modes was found in seismic models of Nu Eri
built with the OP data, but at frequencies higher than those measured in the
star. No such instability was found in models of 12 Lac. We do not have yet a
satisfactory explanation for low frequency modes. Some enhancement of opacity
in the driving zone is required but we argue that it cannot be achieved by the
iron accumulation, as it has been proposed.
