  We present refined color-color selection criteria for identifying Wolf-Rayet
(WR) stars using available mid infrared (MIR) photometry from WISE in
combination with near infrared (NIR) photometry from 2MASS. Using a sample of
spectrally classified objects, we find that WR stars are well distinguished
from the field stellar population in the (W1-W2) vs. (J-Ks) color-color
diagram, and further distinguished from other emission line objects such as
Planetary Nebulae, Be, and Cataclysmic variable stars using a combination of
NIR and MIR color constraints. As proof of concept we applied the color
constraints to a photometric sample in the Galactic plane, located WR star
candidates, and present five new spectrally confirmed and classified WC (1) and
WN (4) stars. Analysis of the 0.8-5.0 micron spectral data for a subset of
known, bright WC and WN stars shows that emission lines (primarily He I) extend
into the 3.0 - 5.0 micron spectral region, although their strength is greatly
diminished compared to the 0.8-2.5 micron region. The WR population stands out
relative to background field stars at NIR and MIR colors due to an excess
continuum contribution, likely caused by free-free scattering in dense winds.
Mean photometric properties of known WRs are presented and imply that reddened
late-type WN and WC sources are easier to detect than earlier-type sources at
larger Galactic radii. WISE W3 and W4 images of 10 Wolf Rayet stars show
evidence of circumstellar shells linked to mass ejections from strong stellar
winds.
