Pupae of Aedes aegypti, Ae. triseriatus and Culex restuans dive less frequently when resting in a concave meniscus than when resting in open water. They also tend to terminate diving after contacting submerged vertical surfaces, increasing their chances of surfacing in a concave meniscus. As a result pupae tend to rest in concave menisci associated with emergent vertical surfaces, a behavioral adaptation by which they probably conserve energy and avoid predation.