There are many species of brushfooted butterflies that overwinter as half-grown larvae. Included in those are the checkerspots of the genera Euphydryas, Chlosyne, Poladryas, and Thessalia. When brought out of hibernation, make sure you have fresh host plant to feed them. Also, with checkerspot caterpillars, it is critical that you properly separate larvae on the hostplant; so that they do not feed for an instar and then re-diapause. In other words rear them in a small container with only one or two larvae per container. If they sense too many sibling caterpillars and insufficient host in one container, they will re-hibernate as a defense mechanism against starvation.