Wikipedia
Hybotidae
"Dance fly" and "dance flies" redirect here. This term is also used for some Empididae.
Hybotidae, the typical dance flies, are a family of true flies. They belong to the superfamily Empidoidea and were formerly included in the Empididae as a subfamily.
Some, such as Tachydromia, are predators that run around on the bark of trees in complex pattern, hence the common name. Tachydromia species are only about three millimeters long.