A detailed study of the larval and pupal stages of a bilateral gynandromorph obtained from a hybrid cross between Citheronia regalis (Fabr.) and C. splendens (Druce) (Lepidoptera: Saturniidae) is presented. Color illustrations and metric data document male splendens characteristics on one side and female regalis characteristics on the other side of the last instar larva. Differences in color, shape, and setal positions on the head capsule and the anal plate are documented. A video study of the larval gynandromorph is presented from a hyperlink within this publication. The pupa shows evidence of male and female genitalia, however, no asymmetry was observed among the sclerites of the antennae or of the wings. Images of the adult gynandromorph are included.