FIG. 1.—Modular analysis of courtship in Rhŋacotriton and plethodontids. Modules are labeled: AP ¼ approach, HC ¼ head contact, TSW ¼ tailstraddling walk, SD ¼ spermatophore deposition, and POS ¼ positioning. Courtship sequences flow from left to right (as indicated by large arrows) and from top to bottom within modules. Behaviors shown in the same color occur in the same temporal context. Behaviors shown with different shades of the same color occur in a predictable sequence; those in lighter shades occurring earlier than those shown in darker shades. See Fig. 2 for inventory of behavior by module and submodule.