Stilt-Legged Flies – Family Micropezidae

Stilt-Legged Flies

Rainieria antennaepes

Rainieria antennaepes

Live adult flies photographed & filmed at Black Partridge Preserve, Cook County, and Ogle County Illinois, USA.

I would have called this the “semaphore” fly, because it constantly waves its front legs around as if signaling with flags.

Rainieria antennaepes

Say, (Thomas Say 1787-1834) in his original description of the family, states:

“The anterior pair of feet, when compared with the others, are very short, and being extended before the head, considerably elevated above the plane on which the insect moves, and also being constantly vibrated, they assume the appearance of antennae. The whiteness of the anterior tarsi is very distinct and characteristic.”

Taeniaptera trivittata

Taeniaptera trivittata

Similarly, male flies in the family Dolichopodidae, commonly called “long-legged” flies (below) have “mittens” on their front legs, which they also wave about. These mittens are secondary sexual characteristics and attract females.

Long-Legged Fly Dolichopus

Long-Legged Fly, Family Dolichopodidae

Family Micropezidae consists of about 40 genera with 475 described species worldwide. I have always found these gentle creatures in wooded settings most often near flowing water.


  1., Micropezidae
  2., Taeniaptera trivittata
  3., Rainieria antennaepes

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Tree Encyclopedia / North American Insects & Spiders

Online since 2002