Giant ichneumon wasp (Megarhyssa macrurus)

I was digging up the irises around the birch stump today. We're going to have it ground down so we can plant another tree there. A long insect came zooming by and landed on the stump. I thought it was a dragonfly until I saw its tail.
My goodness! Is that a stinger? I grabbed my camera to take some photos. When the creature start to lift and flare its abdomen, I backed off, thinking that was some kind of threat display.

Then I went inside to look up what it was. What she was – a female Megarhyssa macrurus, or giant ichneumon wasp. What I thought was a stinger is really a 6-inch-long ovipositor. She was looking for holes bored by her rival, a pigeon horntail wasp.
When she finds one, she lifts her abdomen high in the air and draws that long ovipositor forward until she can push it straight down into the hole, guiding it with her hind legs. In the hole is the larva of her rival, which she stings and paralyzes. Then she lays an egg, which will hatch and eat the paralyzed larva, then pupate and become an adult wasp the next spring.
Ew, right? But very interesting. It's so specifically evolved. (If you're not too squicked out, click to see the photos larger; they're pretty cool.)

It's funny, the Sergeant and I were discussing the theory of intelligent design and its flaws just last night. Turns out Darwin had something to say about that, involving the ichneumonidae's gruesome habits:

I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of Caterpillars, or that a cat should play with mice.

Thanks to the fine contributors to Wikipedia for expanding my insect horizons. And thanks to Ms. Wasp for stopping by. I'm sorry that your efforts will be in vain.