  Massive evolved stars loss a large fraction of their mass via copious stellar
wind or instant outbursts and during certain evolutionary phases they can be
identified via the presence of their circumstellar nebulae. In this paper, we
present the results of search for compact nebulae (reminiscent of circumstellar
nebulae around evolved massive stars) using archival 24 $\mu$m data obtained
with the Multiband Imaging Photometer for Spitzer. We discovered 115 nebulae,
most of which bear a striking resemblance to the circumstellar nebulae
associated with Luminous Blue Variables (LBVs) and late WN-type (WNL)
Wolf-Rayet (WR) stars in the Milky Way and the Large Magellanic Cloud (LMC). We
interpret this similarity as an indication that the central stars of detected
nebulae are either LBVs or related evolved massive stars. Our interpretation is
supported by follow-up spectroscopy of two dozens of these central stars, most
of which turns out to be either candidate LBVs (cLBVs), blue supergiants or WNL
stars. We expect that the forthcoming spectroscopy of the remaining objects
from our list, accompanied by the spectrophotometric monitoring of the already
discovered cLBVs, will further increase the known population of Galactic LBVs,
which in turn would have profound consequences for better understanding the LBV
phenomenon and its role in the transition between hydrogen burning O stars and
helium burning WR stars. We also report the detection of an arc-like structure
attached to the cLBV HD326823 and an arc associated with the LBV R99 (HD269445)
in the LMC.
