We present a study of the mid-infrared properties and dust content of a
sample of 27 HII ``blobs'', a rare class of compact HII regions in the
Magellanic Clouds. A unique feature of this sample is that even though these
HII regions are of high and low excitation they have nearly the same physical
sizes ~1.5-3 pc. We base our analysis on archival 3-8 microns infrared imagery
obtained with the Infrared Array Camera (IRAC) on board the Spitzer Space
Telescope. We find that despite their youth, sub-solar metallicity and varied
degrees of excitation, the mid-infrared colors of these regions are similar to
those of typical HII regions. Higher excitation ``blobs'' (HEBs) display
stronger 8 micron emission and redder colors than their low-excitation
counterparts (LEBs).Comment: 8 pages, 4 figures, Accepted for publication in Astronomy &
Astrophysics (higher resolution version is available in
http://www.physics.uoc.gr/~vassilis/papers/blobs_spitzer.pdf