Live females of woodnymphs (genus Cercyonis) seem to prefer to oviposit on dead grass blades as these butterflies overwinter as unfed first instar. After you obtain eggs from females, it generally takes the ova 17 to hatch in the lab. It is possible to force them out of diapause by providing young larvae with VERY healthy grass blades.  It takes caterpillars about three months to go through to adult; so, you may be feeding woodnymph caterpillars grass through the holidays :o)