Rhamphomyia longicauda, the long-tailed dance fly, is a species of fly commonly found in eastern North America that belongs to the family Empididae and part of the superfamily of dance flies Empidoidea. It is included in the subgenus Rhamphomyia. This species of fly is most known for sex role reversal during courtship, as females put on exaggerated displays and congregate in leks to attract males. Females cannot hunt for food, so they receive protein from nuptial gifts brought to them by males. Female dependence on males for nutrition is the principal cause for sex role reversal in this species of fly.

Empididae is a family of flies with over 3,000 described species occurring worldwide in all the biogeographic realms but the majority are found in the Holarctic. They are mainly predatory flies like most of their relatives in the Empidoidea, and exhibit a wide range of forms but are generally small to medium-sized, non-metallic and rather bristly.