UCAC2 3350701 , the SIMBAD biblio

We present UBV (and some Hβ) photoelectric photometry of some 100 luminous star candidates in each of two 10°-15° wide longitude zones centered symmetrically relative to the Galactic center in the Milky Way at longitudes l=±45°. The southern field contains significantly more massive stars than the northern field, suggesting a real asymmetry. This accords with the remarkable lack of known Wolf-Rayet stars in the northern zone as opposed to 14 known in the southern zone. If this is not just a local fluctuation on a kiloparsec scale, it is not obviously related to the known bar in the Galaxy.