Andromica clearwing, Tatama National Park, Colombia
Quite noisy as this was taken at a distance with the tele lens in low light. This likely is the Greta andromica andromica sub species, based on a detailed checklist of Montezuma butterflies. Here's the checklist (warning: big file):
''Greta andromica'', the Andromica clearwing, is a ithomiine butterfly from the subfamily Ithomiinae. It was described by William Chapman Hewitson in 1854.