Heliconius melpomene possibly.

Carol Palmer, docent at the Tucson Botanical Garden Butterfly House says: "should be a Small Postman, Heliconius erato, Family Heliconidae, from Central and South America, flies year round, Laval food plants are Passifloraceae, Passion Flowers. I have been told that the reason they are called postman is their habit of following a certain route, repeatedly visiting the same plants. It is always difficult to be exact on the Longwings like the Postman which come in several forms, and are also mimicked by other butterflies. Since the Passion Vine is somewhat poisonous the postman and other caterpillars who feed on it will retain distasteful properties if eaten. Consequently the more tasty butterflies try to mimic the patterns and colors of them, thereby gaining a certain amount of protection by mimicry.
This is from one of my favorite books for id of the butterflies in the exhibit : 500 BUTTERFLIES FROM AROUND THE WORLD, By Ken Preston_Mafham, from Firefly Books. There are a large number of them in this book." Comment forwarded by Brian Gersten.