The Dance Flies take their common name from the mating swarms formed in some species. In these swarms, the males circle while also flying in an up and down direction.
Another interesting habit in the mating of some Dance Flies is the male's practice of spinning a ball of silk that contains an insect for the female to eat during mating. A number of authors have reported that males of some species have evolved to give the female an empty ball of silk, or even some found object that slightly resembles a ball of silk. The females of these species seem accepting of these dubious gifts. Oldroyd (1964) says this is "like wooing a lady with a diamond necklace, then putting the necklace into a showy box, and finally wooing her with an empty box!"
Adults are mostly predacious. Some are found on flowers. Some seldom fly, but hunt by running down their prey.
The larvae can be found in a whole range of environments, depending on the species: in rotting herbaceous plants, in decaying wood, in the soil, and even under bark.
Dance Flies sometimes resemble Long-legged Flies, but unlike the Long-legged Flies the male Dance Flies do not have prominent genitalia folded away under the abdomen.
A handful of very large genera, including Empis and Rhamphomyia, account for a great many of the Dance Flies most commonly encountered in the Nearctic.
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