  Context. Based on the far infrared excess the Herbig class of stars is
divided into a group with flaring circumstellar disks (group I) and a group
with flat circumstellar disks (group II). Dust sedimentation is generally
proposed as an evolution mechanism to transform flaring disks into flat disks.
Theory predicts that during this process the disks preserve their gas content,
however observations of group II Herbig Ae stars demonstrate a lack of gas.
Aims. We map the spatial distribution of the gas and dust around the group II
Herbig Ae star HD 95881. Methods. We analyze optical photometry, Q-band
imaging, infrared spectroscopy, and K and N-band interferometric spectroscopy.
We use a Monte Carlo radiative transfer code to create a model for the density
and temperature structure which quite accurately reproduces all the
observables. Results. We derive a consistent picture in which the disk consists
of a thick puffed up inner rim and an outer region which has a flaring gas
surface and is relatively void of 'visible' dust grains. Conclusions. HD 95881
is in a transition phase from a gas rich flaring disk to a gas poor
self-shadowed disk.
