ABSTRACT
Chironomids, mayflies, and other groups of insects emerge simultaneously following cues involving the phase of the moon or the tides, local weather conditions, or seasonal changes to synchronize their emergence from the water as adults and begin mating and depositing eggs. When the human bait passes near a swarm of Psorophora varipes, the mosquitoes suddenly take to the air and emerge in large swarms to surround their victims, attacking from all directions. This translates as "the Devil's horsemen". It is likely that those dragonflies that use people as bait would follow the early explorers of Brazil throughout the day waiting for them to attract mosquitoes for them to eat. This location in the freshwater section of the estuary seemed to be one in which species in the family Chironomidae could be expected to develop. The dragonflies gain several advantages by using vertebrates as bait, in addition to the obvious one of gaining access to a large food supply.
