This long winged butterfly is known as an Ismenius. I’ve confused it in the past with the Tiger Longwing (Hecale) butterfly. The markings are similar, but there is a clear difference with the wings open. The Tiger Longwing has a solid brown area on the back. The ismenius has the black stripes on both sides of the wings.
These are common at Butterfly Worlds, and I never tire of capturing images of them. They tend to rest for long periods on leaves or hanging from vines. This one was captured at f2.8, ISO 320, 1/200 of a second with my Canon 100mm f2.8 macro lens.