Bolometric X-ray luminosity (L_X,bol) histogram of SPIRE-detected (dashed cyan histogram) and SPIRE-undetected (dashed blue histogram) X-ray AGN hosts. Though the conversion to L_X,bol is extremely uncertain and though we do not explicitly use this quantity in this work, the histogram is used to show the rough range and completeness limit of the X-ray AGN in our sample. L_X,bol is derived from the spectroscopic or photometric redshift and XMM/EPIC hard band X-ray luminosities (i.e., 2–10 keV) using the coversion from Vasudevan & Fabian (2007; see text). The rough completeness of the XMM imaging is L_X,bol ≳ 3 × 10⁴⁴ erg s^-1, corresponding to a moderately powerful Seyfert. Note that most of the SPIRE-detected hosts of X-ray AGN lie at the more powerful end of the L_X,bol distribution.