Wasp wipes sweat off her brow on a hot day.
Well I'm pretty sure they don't sweat, but she had gone for a swim immediately prior to the photo.
Technical note: Also for those following along at home I'm sure this is in the Polistes genus. I'm going to wildly guess Polistes dominulus, but that's only really because I know it doesn't have the distinctive markings of P. aurifer or P. exclamans. She lacks the black stripes typical of dominulus though, so I'll get back to you one that.
I have also put the rest of my pictures of wasps, bumblebees, yellowjackets, dragonsflies and other things that have randomly landed on my hand to be photographed.
And yes I'm a jerk who doesn't put huge pictures behind lj cuts. You just can't be in-your-face with a scary close-up of a wasp if it's behind an lj cut! If you're still bothered, here's another picture for you.