,
V. S. Strelnitski 
,
J. Martín--Pintado 
,
H. E. Matthews 
,
H. A. Smith 
Institut de Radio Astronomie Millimétrique,
France
Laboratory for Astrophysics, National Air and Space Museum,
Washington, D.C., USA
Centro Astronómico de Yebes, Apartado 148,
E--19080 Guadalajara, Spain
Joint Astronomy Center, 660 N. A`ohoku Place, University Park,
Hilo, Hawaii 96720, USA 
--line s out of six observed in the frequency range
from 100 to 400 GHz toward the radio star MWC349A.
The detected 
--line s have similar parameters as the pedestal features
of the short mm 
--line s and probably have the same origin in the ionized wind.
We find that the flux ratios of 
-- and 
--line pedestals of nearly the same
frequency are much smaller than expected from an optically thin plasma
in LTE in all cases. We show with the help of simplified NLTE
models of the recombination line emission that low 
--ratios are
due to enhancement of the 
--line s by stimulated emission. This is
a natural consequence of the high free--free continuum opacity in the
ionized wind of MWC349A. The models also predict that the 
--ratio is
a sensitive probe of the electron density. For the 
line emitting region the density thus derived is compatible
with previous estimates, 
cm
, based on
a model of the wind's continuum emission.
The four newly detected 
--line s provide, together with the high frequency 
--line
pedestals, the most reliable value of the center velocity of the ionized
outflow, 
kms
. This value agrees well with the
centroid velocity of the disk, 
kms
,
as derived from the velocities of the blue and red maser spikes,
and thus represents the best estimate of the stellar velocity.
H
, at 366.6 GHz the highest frequency 
--line
observed to date, displays on top of the pedestal two
weak narrow emission features whose velocities and widths
are in qualitative agreement with those of the 
--line maser spikes. We
tentatively interpret these H
spikes as a weak disk maser whose estimated
optical depth, 
, confirms earlier estimates of the 
--line maser
gain (
).