Metamorphosis for this butterfly appears to have been interrupted by a parasite, a small wasp perhaps. You can see the hole where the parasite chewed its way out. Oddly, there’s a similar hole on the other side. Maybe it abandoned this other exit since it looks incomplete. Or maybe there were actually multiple parasites.
I know this is the chrysalis of a brush-footed butterfly in the family Nymphalidae because other butterfly families use a a small silken thread around the thorax to help secure it. Here’s an example from an earlier post.
Butterfly chrysalises can be quite intricate and this one has some interesting flourishes.
I suspect this caterpillar is closely related to similar looking nymphalid butterfly caterpillars in the genus Adelpha. Some are generally referred to as moss caterpillars because the various body projections give the appearance of moss. It may not be obvious from these photos, but check out this photo from Flickr user artour_a.
I’ve encountered a similar caterpillar before in a different part of Brazil, although that one was probably an earlier instar and was shades of brown.
I usually don’t have the patience to stalk butterflies. The colors on this one were just so vibrant that I spent about 20 minutes chasing after it.
Even the undersides of the wings, while definitely muted, are attractive (to me anyway).
Glasswing butterflies lack scales on parts of their wings, leaving those parts transparent.
Though similar looking, this is not the species (Greta oto) commonly found in many of the butterfly houses I’ve visited. That one’s range doesn’t extend into South America. This is probably a closely related species. I was surprised there are so many that look very much alike. Check out this Florida Museum of Natural History page on the tribe Godyridini to get an idea.