Nemoria caerulescens larvae generally resemble the larval form of Nemoria bistriaria or N. bifilata, which Ferguson grouped with caerulescens on the base of genitalic similarities. The larvae we reared would not feed on Rhus trilobata nor on oak leaves, even those from native Quercus gambelii found in the region where adults have been collected. They fed slowly at first on exotic oak catkins, though no oaks are in flower at the time that eggs are laid so this is not a possible natural food source. Larvae would not feed on numerous plants that are documented as host plants or have been used to rear other Nemoria species. Larvae rejected several Polygonaceae including an Eriogonum species and also rejected Vaccinium, Juniper, Salix and several Rosaceae. More recently, Dave Wagner has collected larvae in the field and clearly established their native host plant - larvae from natural hosts are striking and are colored quite differently from these lab reared larvae.