  The ionising stellar populations of eleven HII regions in the spiral
galaxies: NGC628, NGC925, NGC1232 and NGC1637, all of them reported to have
solar or oversolar abundances according to empirical calibrations, have been
analysed using stellar population synthesis models. Four of the observed
regions in the sample, show features which indicate the presence of a
population of Wolf-Rayet (WR) stars with ages between 2.3 and 4.1 Myr. This
population is sufficient to explain the emission line spectrum of the low
metallicity region H13 in NGC628. This is not the case for the rest of the
regions for which a second ionising population is required to simultaneously
reproduce both the WR features and the emission line spectrum. For two of the
regions showing WR features, no consistent solution is found, since the
population containing WR stars produces a spectral energy distribution which is
too hard to explain the emission of the gas. Several solutions are proposed to
solve this problem.
