a) The r⁺ −  [24]  color distribution of the MIPS 24μm sources as a function of redshift in the COSMOS field. Galaxies selected as OFIR sources are characterized by r ⁺  −  [24]  colors redder than the threshold indicated by the dashed line. This criterion effectively selects galaxies at 1.5 < z < 3. The typical uncertainties on the r ⁺  −  [24]  color have been calculated at 1.5 < z < 3 and are shown in the right corner. b) Redshift distribution of the OFIR galaxies with F_24   μm > 0.08 mJy (blue filled histogram) compared to the redshift distribution obtained for the full MIPS-selected galaxy population in COSMOS (black solid line). c) Redshift distributions derived from the MIPS sample restricted to sources with F_24   μm > 0.3 mJy (same color definitions as in (b)). The relative contribution of the OFIR galaxies at 1.5 < z < 3 increases with mid-IR luminosities.