Probably Robber Fly

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.

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