Family Empididae - Dance Flies

Balloon Flies, Empids, Dagger Flies

used to be treated in a broad sense to include all the Empidoidea except Dolichopodidae(1)(2)(3); here treated as defined in(4)(5), with the subfamilies Hybotinae, Ocydromiinae, and Tachydromiinae treated in Hybotidae; Brachystomatinae, in Brachystomatidae

=Empidae

Empididae Latreille 1804

~460 spp. in >30 genera of 3 subfamilies in our area(3), >3,140 spp. in >100 genera total(6)

Small to medium sized flies, usually elongated and mostly dark colored. They have a rounded head and a distinct neck, a large and humpbacked thorax and long tapered abdomen. The legs are slender and sometimes the front legs are raptorial, for grasping other insects. The proboscis is often long and pointed.(5)

Worldwide

small insects, and occasionally nectar; larvae often feed on decaying organic matter in the soil, some are predatory

Larvae found in a variety of situations--aquatic, semiaquatic, in dung, in bird nests, among roots and fungi(3)

In mating swarms, males fly up and down in a sort of dance. They have captured an insect, wrapped it in silk, and hold as an offering for females. Females seem to choose the male with the most enticing offering. Sometimes a male may offer just an empty ball of silk.

Males with "nuptial balloons"

Paul Beuk on swarming: