A group of us went to Butterfly World in Coconut Creek, Florida (Tradewinds Park). I borrowed a Canon 40D because mine was in the shop being repaired. But I used my own trusty 300 f/4 L because of its sharp, close-focusing ability and the great image stabilization. It also has wonderful bokeh as you can see in this photo.
The photo here is of the Paper Kite (Idea leuconoe), a butterfly commonly found in Thailand, Malaysia and Borneo. These are a very attractive species and are often cultivated and are perfect for Butterfly World. Idea leuconoe is also known as the Rice Paper or Three Nymph. They look like tasty treats for birds but apparently all of the Idea genus are poisonous to the flying creatures.
You can see the others in this collection by clicking on the link above for my gallery. There is a slide show with a selection. I used natural light which was generally nice and soft early in the day but got distinctly more contrasty later on. All the photos were brought into Lightroom 5 where they were gently processed.
I recently found a website about photographing butterflies this has some decent tips.