The Giant Helicopter Damselflies of tropical America are members of the mostly New World family Pseudostigmatidae. They are large but slender species, adapted to life in dense forests where the females oviposit in soft moist wood-rot at the margin of tree holes. Larvae are predatory and feed on each other and on other species of aquatic organism sharing the habitat. Adults fly through the understory in search of the webs of orb-weaving spiders upon which they prey by seizing and pulling them out of their webs. Megaloprepus caerulatus is the most spectacular of this group, with the longest wing span of any living Odonata.