Big nasty horse fly on my car the other day just after a thunderstorm.
I'm usually pretty tolerant of bugs but I don't like horse flies. They'll buzz your head and harass you when you're hiking in the woods and their bites hurt like a bitch. After a few miles of buzzing dive bombs from a determined horse fly, I've been known to snap, pick up a stick, and start swinging it through the air like a madman, and screaming death threats to an insect.
Females have long, sharp mandibles that rip and tear out a hunk of flesh for their blood meals (like mosquitoes, only the females need blood for nourishing their eggs). Adult horse flies feed on nectar and therefore play a role in plant pollination.
Close-up is a bit fuzzy but you can see a couple of things. The large compound eyes are separated rather than meeting on top of the head which indicates it's a female fly. Also note the large mandible hanging down from its mouth, another female characteristic.
I like to classify plants and animals I take pictures of with their Latin (scientific) name. Unfortunately, there are hundreds of horse fly species so the best I can do is that it's probably Tabanus sp. where "sp." is just an abbreviation for some species in the genus Tabanus. It is, of course, a true fly (diptera) like the house flies it so closely resembles.
Even though I dislike these guys, and it will probably bite me next time I mow my lawn, I didn't kill it. I just got it the car and drove down my driveway until it blew off.