As far as what tipped me off it was a beetle, I didn’t know until it settled down, folded its wings, and looked beetle-like. The thing is, I learned back when I was a kid that wasps or hornets that approach you slowly are almost never intent on stinging you – the ones that mean you harm come in like a bullet, and sound like they are in overdrive. So, if one flies up slowly and lands on you, the best bet is just to stop moving and have a look at it (and at this point, I said “Hey, it’s not a wasp, it’s a a beetle! I’ll catch it!”). Most of the time, a wasp or hornet will crawl around a bit, maybe lap up some of your sweat, and then be on its way.

On the other hand, in my experience the instinctive “running in circles and flailing” response practically guarantees getting stung. The time when running and flailing makes a little sense is when you have knocked over a major nest and they are a-coming for you, but in that case you want to move away in a straight line, while preferentially flailing around your head and face to force them to go for your arms, legs, and torso instead. Once you get beyond their defense perimeter, they generally drop the chase and go back home. Distance is your friend. I don’t recommend running, though, because you usually only need to move away about 20-30 feet, which only takes about ten seconds. Trying to run, tripping, and falling down while you are still too close to the nest will make it so very, very much worse . . .

* At least, not in the situation you described, where it was either “something landed on my arm. Oh, it’s a beetle,” or “aaaah!”, followed by running in circles and flailing.

What about the appearance tipped you off to its being a beetle and not a wasp?