What kind of butterfly is this?

[Buckingham U. Badger]

What kind of butterfly is this:

A few days ago (September 18, 1999),
my daughter told me that a butterfly stung her.  I told her that
butterflies don't bite
or sting.  But she showed me the mark on her finger, and it looked like
a bee sting.
Three days later, her finger was itching "like a mosquito bite", but
more annoying.

My daughter is more than old enough and smart enough to know the
difference
between a butterfly and a bee, so please don't suggest that it was a
case of
mistaken identity.  She described the butterfly as having white wings,
and being about 1 1/2 inch (4 cm) long.  She said that the butterfly had
been
flying close to the ground, and that she thought its manner of flight
was unusual
for a butterfly: not graceful, but jerky, flying in circles, almost as
if confused or
attacked.  Later the same day, she showed me such a butterfly at another
place
(about 3 miles away), and it was indeed behaving as the one she had
described.

This all happened in Eau Claire, Wisconsin, USA.

What kind of butterfly is this, that either bites or stings?  What other
information do
you have about it?  We're not worried about the injury; that's very
minor.
We're curious!

Thanks for any information,

Ted Shoemaker
tshoemaker at students.wisc.edu

on behalf of my very curious daughter Christina.