Evan,
Yes, it is generally true that in Aroids the female flowers are receptive first, then on male anthesis (pollen drop) the female flowers are no longer receptive. The female flowers are usually only receptive for about a day - sometimes just a few hours, although in some cases you can "pre-pollinate" (i.e. apply pollen prior to female receptivity) and get successful take - this is true of Caladiums and may be true for some other genera. Many Aroid blooms signal female receptivity by an increase in temperature of the spadix - some dramatically so.
I've come up with some pretty exciting Typhonium hybrids using T. trilobatum as my primary breeding platform. I've got silvery veins and/or maroon spots on a plant of the size of T. trilobatum, plus various types of leaf divisions, from fully pedatisect to trilobed and some in between (see picture below). I do want to get S. venosum involved, though, as a successful cross with it would yield, potentially, some even more spectacular progeny.
LariAnn
