Podosesia aureocincta Purrington and Nielsen is a sibling of P. syringae, the lilac borer. It is distinguished from the latter species by its larger and smoother egg, by larval crochet reductions, and by its later adult flight period. Larvae bore in the wood of living ash trees and overwinter as 2nd instars, whereas P. syringae larvae overwinter as final instars. The synthetic sex attractant used successfully to capture male P. syringae is ineffective for P. aureocincta, suggesting that sex pheromone divergence has occurred.