  The GLIMPSE (Galactic Legacy Mid-Plane Survey Extraordinaire) Point Source
Catalog of ~ 30 million mid-infrared sources towards the inner Galaxy, 10 < |l|
< 65 degrees and |b| < 1 degree, was used to determine the distribution of
stars in Galactic longitude, latitude, and apparent magnitude. The counts
versus longitude can be approximated by the modified Bessel function
N=N_0*(l/l_0)*K_1(l/l_0), where l_0 is insensitive to limiting magnitude, band
choice, and side of Galactic center: l_0= 17-30 degrees with a best fit value
in the the 4.5 micron band of l_0=24 +/- 4 degrees. Modeling the source
distribution as an exponential disk yields a radial scale length of H= 3.9 +/-
0.6 kpc. There is a pronounced north-south asymmetry in source counts for |l| <
30 degrees, with ~ 25% more stars in the north. For l=10-30 degrees, there is a
strong enhancement of stars of m= 11.5-13.5 mag. A linear bar passing through
the Galactic center with half-length R_bar=4.4 +/- 0.5 kpc, tilted by phi=44
+/- 10 degrees to the Sun-Galactic Center line, provides the simplest
interpretation of this data. We examine the possibility that enhanced source
counts at l=26-28 degrees, 31.5-34 degrees, and 306-309 degrees are related to
Galactic spiral structure. Total source counts are depressed in regions where
the counts of red objects (m_K-m_[8.0] >3) peak. In these areas, the counts are
reduced by extinction due to molecular gas and/or high diffuse backgrounds
associated with star formation.
