Check out that moustache!

Once you see the powerfully built robber fly of the Asilidae family, with its huge eyes, short proboscis and bristly "moustache," you won't forget it. It's an aggressive predator known for its speed, its strength, and its power.

The robber fly lies in wait and ambushes flying insects, including honey bees, syrphid flies,  grasshoppers, dragonflies, damsel flies and others--many larger than it is. Scientists say the robber fly stabs its prey with its short, powerful proboscis, injects a paralyzing toxin that liquifies the insides, and then sucks out the content.

Sort of like aficionados of Slurpees at the local Seven-Eleven.

Robber flies are the kinds of things you might expect in a science fiction movies--except this isn't science fiction. They've earned their nicknames of "bee killers" and "assassin flies."

These insects, found throughout much of the world (there are some 7000 species in the robber family Asilidae), can be as long as two inches and as short as 0.2 inches. 

If you look on BugGuide.Net, you can see robber flies attacking other insects, including syrphids or flower flies. 

But check out that bristly moustache! Actually it's called a mystax, derived from the Greek mystakos, which mean "moustache" or "upper lip." Some entomologists think the mystax provides some head and face protection for the robber fly when honey bees and other would-be prey fight back.