(A) Mirante river and respective margins where the predation event was observed, located in the Brazilian Atlantic Forest, Intervales State Park, São Paulo state, Brazil. (B) Structure of the three-dimensional web of Helvibis longicauda and (C) an adult female resting on the web while protecting its egg sac. (D, E) Choeradoplana cf. gladismariae preying on H. longicauda, which is still trying to protect the egg sac while being constricted and covered with sticky mucus. (F) Detail of C. cf. gladismariae after being purposely separated from the spider for photography.