Transformations: Catalpa Sphinx Moth

Catalapa sphinx moth caterpillar, finding a place to pupate underground, 9 August 2026 (photo by Kate St. John) 2 September 2026 For insect novices like me, August is the easiest time of year to find any life phase of the catalpa sphinx moth (Ceratomia catalpae). In August the caterpillars are large and their bodies signal that it’s time to stop eating and start pupating. They drop from the trees and burrow underground to overwinter and pupate. That’s where I found the caterpillar pictured at top in early August. How did he reach that stage? Here are some of the steps in his transformation. 1. His parents pupated and emerged in April or May. They are well camouflaged in the woods but not as interesting as the last instar. Adult catalpa sphinx moth (photo from Wikimedia) 2. His mother looked for a catalpa tree and laid her eggs on the undersides of the leaves. Catalpa sphinx moth eggs (photo by Lacy L. Hyche, Auburn University, Bugwood.org) 3. By June in Pittsburgh northern catalpas…