The backwash from this sucker's prop almost knocked me down yesterday when it did a fly by with a dismembered leaf beetle held tenderly in its front paws, impaled on its proboscis. This is the largest (and most stately, imho) of the Laphria complex flies, a truly stunning insect.

There are over 7,000 species of robber flies world wide; nearly 1,000 in North America.  All robber flies have stout, spiny legs, a dense moustache of bristles on the face (mystax), and 3 simple eyes (ocelli) in a characteristic depression between their two large compound eyes. The mystax helps protect the head and face when the fly encounters prey bent on defense. The antennae are short, 3-segmented, sometimes with a bristle-like structure called an arista. The short, strong proboscis is used to stab and inject victims with saliva containing neurotoxic and proteolytic enzymes which paralyze and digest the insides; the fly then sucks the liquefied meal much like we vacuum up an ice cream soda through a straw. Many species have long, tapering abdomens, sometimes with a sword-like ovipositor.

Male Bumble Bee

Female Robber Fly

Male brownbelted bumble bee vs. female Laphria thoracica