Meet the moot-moots
At lunch, the mystery was solved when one of the girls noted, "oh, you got bitten by the moot-moots!" Apparently, they're tiny biting flies that are at their worst mid-morning -- exactly when we were outside. To my very great surprise (and initial puzzlement), the bites weren't itchy at all, but apparently I'm lucky that way. Some people don't find them the slightest bit itchy while others nearly go mad.