This is a Doris Longwing (Laparus doris viridis). Photographed in the butterfly room at the Calgary Zoo Conservatory, August 23rd. It was an absolute Zoo at the Zoo that day - a last minute chance for kids before school starts!
Thanks to bayucca for the full ID name: Laparus doris viridis.
Interesting - can't save tags this morning. What's up, Flickr? OK, they suddenly appeared maybe an hour later, ha.