Eggs were laid by a female captured at MV light. They wintered and the first was found hatched May 4, 2009. I supplied Populus tremuloides for rearing. I photographed presumed penultimate and/or final instars on May 19. Since this was a batch rearing more than one caterpillar is shown (two, I think). The largest with extensive white markings was about 38 mm. All caterpillars were released on May 26, some of them prepupal.