Fig. 3. Double helicoidal wall design. A in The Pupation Chamber of Dung Beetles (Coleoptera: Scarabaeidae: Scarabaeinae)

Fig. 3. Double helicoidal wall design. A helicoid develops downward to the inferior pole (A), leaving space between whorls to lodge the whorls of the second helicoid, which develops upwards after changing its orientation in the inferior pole (B). These trajectories are complementary and when they are superposed, they form the helicoidal wall (C).