The foraging behavior of the millipede-specialized predatory ant Leptogenys cyanicatena was observed in Chiang Mai Province, northern Thailand. During the observations, millipede species from two families of the orders Polydesmida (family Paradoxosomatidae) and Spirostreptida (family Harpagophoridae) were hunted by L. cyanicatena. Lone foragers searched for millipedes on the forest floor. When a forager encountered a millipede, she touched the latter with antennae and mouthparts for up to 15 seconds, but never attacked the prey alone. Alternatively, she would then quickly return to the nest to recruit nestmates (scout behavior). Once the scout arrived at the nest entrance, a raiding party would be quickly formed upon stimulation. The scout would then lead the raiding party, consisting of 7\textendash 155 ants, and move towards the prey-discovery site in a single file. If the target millipede escaped from the original site, the ants of the raiding party would find the escapee by following its trail. Im- mobilized large millipedes were retrieved by ``self-assembling chains'' as reported in a previous study. Nestmate recruitment is necessary not only to retrieve, but also to immobilize prey, because the mil- lipedes are too large to be successfully attacked by a single ant. Therefore, scouts recruit nestmates in advance of the attack.