100 More Species #27: Ommatius Robber fly

[urbpan]

Robber fly, family Asilidae
EDITED TO ADD: Ommatius sp.

Robber flies are predatory flies often seen feeding on other flies. Some robust species are adapted for hunting bees, and some are themselves bee mimics. Most of the time people encounter them perched, as the individual pictured here is. The posture is distinctive, and reveals their long legs, which are used to catch prey in mid flight. Once the prey is captured the robber fly feeds in a matter similar to a spider: it injects a paralyzing neurotoxin and digestive enzymes, then drinks the insect dry. Robber flies will perch on humans harmlessly, but if you try to catch one in your hand it may bite you. These photos have been at Bugguide for over a week, but no robber fly specialist has made a more specific identification. There are over a thousand species of robber flies in North America.

EDITED TO ADD: My pic on bugguide was moved to genus Ommatius on 6/17/2013.

Comments

[ursulav.livejournal.com]

Saw a robber fly dining on a honeybee just this morning! They're pretty common in my garden, and fortunately, not inclined to bite!

[wirrrn.livejournal.com]

Saw one of the enormous Perth species the other day, binomial slips my mind. Easily the size of my index finger