Strange Butterfly

I saw this little 1/4 inch (5mm) butterfly on our porch railing.

I watched it for awhile as I photographed it.

The butterfly moved a bit too quickly and it's body seems wrong for a butterfly.

I think it may be a different sort of insect in a butterfly's clothing.

Anyone out there in Blipfotoland know what this little butterfly's name is, or if it is in fact an imposter?