Currently viewing the category: "Robber Flies"
What's That Bug? does not endorse extermination

Subject: Flying “Bee” that eats flies…
Location: Pacific Northwest
October 4, 2016 5:34 am
The Pacific Northwest always seems to come up with tales of strange creatures…BigFoot, D.B Cooper, the Puget Sound Monster…and now a mysterious flying insect that feeds on flies.
I’ve witnessed this assassin do its work usually during the Summer months (actually, I’ve only seen it during the Summer months) and is most active during daylight hours.
It resembles a black and white bumble bee (the white almost exactly replacing the yellow areas of the common bee). Its predatory method is to hover around wherever there are flies, and amazingly will swoop down on top of a fly before the fly knows what hit it. After a few seconds, predator and prey fly off into the sunset.
But the assault is even more interesting. I bore witness to the process while these mysterious fly-eaters did their work on the sunny-side of my tent while camping in Oregon. The flies were congregating on the Western side of the tent, around 1pm, and there were a lot of them. Big and small (so I don’t know how many species there were). Out of no where a flight of these assasin bugs began hovering over the flies. They would swoop in and lans on top of their target. Then, as they allowed me close enough to witness, they spin the fly over and over as their pincers clip off their victim’s wings and legs before flying off with only the torso remaining. It was rather cool to see…there were many of the assassins, and over the course of an hour I witnessed a thousand legs and wing fall along the side of the tent.
I’ve seen these bugs from the Columbia River Gorge, to metropolitan Portland, OR, to the Oregon/Washington Coast.
(Apologies for no pictures, and it isn’t for lack of trying. I have tried many times, but those little buggers are pretty darn quick…and small.)
Signature: Please Bug Me

Bee Killer Eats Wasp

Bee Killer Eats Wasp (from our archives)

Though you did not provide an image, we found your letter highly entertaining, and we believe you observed one of the predatory Robber Flies that mimics a bee.  There is one species known as a Bee Killer in California, Mallophora fautrix, but we don’t know if it is also found in Oregon.  Another possibility is a Bee-Like Robber Fly, Laphria astur, that is found in Oregon and is pictured on BugGuide.  There are also many other possible species, but without an image, we do not want to speculate.

What's That Bug? does not endorse extermination

Subject: Flying insect
Location: Canarian island
September 17, 2016 4:05 am
I foundation this insect on my Windows in Gran Canaria
Thatcher insect is +/- 4cm long.
It is dangerous?
Signature: Insect

Robber Fly

Robber Fly

This is a Robber Fly, and here is a very similar looking individual posted to Getty Images.  While a large Robber Fly might bite a person if it is carelessly handled, they are not aggressive towards humans, but they are predators that frequently hunt on the wing.  Based on this Alamy image, your individual might be Promachus latitarsatus.  The species is also pictured on Biodiversidad Virtual, and an image on Diptera Info shows a large Robber Fly eating a Dragonfly.

What's That Bug? does not endorse extermination

Subject: Giant fly/bee thing?
Location: Maryland
September 10, 2016 5:28 am
Today on my bus route I had an unexpected passenger. I live in Maryland and we had a heat index of 108 at the time. He/she was a very loud flyer and looks like a cross between a bee and a fly and did not seem to want to go outside. Please help me identify him/her.
Signature: Notsocrazy

Red Footed Cannibalfly

Red Footed Cannibalfly

Dear Notsocrazy,
This predatory Robber Fly is commonly called a Red Footed Cannibalfly.

What's That Bug? does not endorse extermination

Subject: A Black & White Bee?
Location: West Los Angeles
September 4, 2016 1:27 pm
Hi Bugman,
Found this creature clinging to a milkweed plant early one morning. Can you tell me what it is?
Signature: Jeff Bremer

Bee Killer

Bee Killer

Dear Jeff,
This is not a Bee, but rather a Bee Killer, one of the Robber Flies in the genus
Mallophora.  The only member of the genus currently known from California is Mallophora fautrix, and according to BugGuide, its range is “sw. US (CA-TX-UT) & Mexico.”  Genus characteristics, according to BugGuide, are “Large, fuzzy, bee-mimicking robber flies” and “Predatory on other insects, including large bees, wasps.”  

What's That Bug? does not endorse extermination

Subject: Demon Insect?!
Location: United States
September 2, 2016 2:01 pm
It’s huge, at least 4.5 inches long, it looks like a dragonfly mixed with a wasp with a fluffy mane, it’s obviously carnivorous because it was just chilling on my porch eating up a wasp.
Signature: Audrey

Possibly Red Footed Cannibalfly eating Wasp

Possibly Red Footed Cannibalfly eating Wasp

Dear Audrey,
This is one of the Giant Robber Flies in the genus
Promachus, and we suspect it might be a Red Footed Cannibalfly.  We also believe your size estimate is an exaggeration. 

What's That Bug? does not endorse extermination

Subject: Please identify the big bug in picture
Location: north Georgia mountains
August 26, 2016 6:03 am
Good morning. A friend took the attached photo earlier this week. and has given his explicit permission for me to do with it what I want, including sharing it/using it. Our community is in the North Georgia mountains, and my friend’s home is located in the lower elevations of the neighborhood, adjacent to the golf course.
There have been a lot of yellow-jackets in the area this year, so we’re happy that something might be attacking them. But, what in the heck is that big something?
Thanks in advance for any assistance you are able to provide.
Signature: Edie

Red Footed Cannibalfly eats Yellow Jacket

Red Footed Cannibalfly eats Yellow Jacket

Dear Edie,
The predator in the image is a Red Footed Cannibalfly, a large species of Robber Fly.  While Robber Flies might bite a person who carelessly tried to handle one, they are not aggressive towards humans.  The unnatural position of the wings of the Red Footed Cannibalfly in your image is somewhat disturbing, leading us to speculate that it is no longer alive and possibly the victim of Unnecessary Carnage.

What's That Bug? does not endorse extermination