Last night, R. was changing T.'s diaper when T. started wailing, full volume, tears rolling down his face. R. was busy saying, "I didn't do anything!" and I pointed out that T. doesn't cry so whether R. did something or not is not relevant; there's obviously something causing him major pain. So we empathized for a minute while removing the diaper and looking him over. No obvious rash. T. grabbing at himself and pulling, which is usually something he does to console himself when he's very upset. I asked him if he wanted Tylenol, and T. just kept bawling, stopping only momentarily to agree verbally that there was an owie. So we went out to the rocking chair and kept looking for something -- a hair, a cut, something!
R. meanwhile is inspecting the diaper. He found a _wasp_ (you knew it was there, because you saw the subject heading. We didn't _have_ a subject heading.). Two theories. (1) Wasps get into this house. We've noticed that and monitor a bunch of likely spots to stop nests outside from developing because we know this is a problem. (2) The diaper cover had been on the line earlier that day. A wasp may have come into the house in the cover, slept through the day, and woken up when compressed against our poor son's bum.
Understandably, the wasp stung T. 3 times. We tylenol'd, benadryl'd and sprayed bactine (with the painkiller stuff in it). Then I watched him like a hawk for about a half hour while I put him to sleep, on the extremely unlikely chance there might be a delayed allergic reaction to the sting. He woke up fine this morning and the swelling is mostly down.
Parenting books do _not_ mention this as a possibility.