  We investigate the relationship between the IR observed properties of the
EXor variables and the mechanisms active during their evolutionary stage. To
this aim, we have constructed a catalog of all the IR (1-100 micron)
photometric and spectroscopic observations appearing during the last 30 years
in the literature. New results of our monitoring program based on near- and
mid-IR photometry and near-IR spectroscopy and polarimetry of one object (V1118
Ori) are presented, complementing those given in a previous paper and related
to a different activity period. Our catalog indicates how the database
accumulated so far is inadequate for any statistical study of the EXor events.
Nevertheless, all the observational evidence can be interpreted into a coherent
scheme. The sources that present the largest brightness variations tend to
become bluer while brightening. The scenario of disk accretion based on viscous
friction between particles agrees with the observations. The new results on
V1118 Ori confirm such a general view. The striking novelty is represented by a
near-IR spectrum of V1118 Ori taken 1 yr after the last monitored outburst: any
emission line previously detected has now totally disappeared at our
sensitivity. For the same source, mid-IR photometry is provided here for the
first time and allows us to construct a meaningful SED. The first polarimetric
data show that V1118 Ori is intrinsically polarized and its spotted, magnetized
surface becomes recognizable during the less active phases.
