Nessaea obrinus

Nessaea obrinus, the obrina olivewing, is a species of butterfly of the family Nymphalidae. It is found from Colombia and the Guianas to the mouth of the Amazon and south to central Bolivia and Mato Grosso in Brazil, extending to northern Argentina.
The length of the wings is 25–40 mm for males and 26–41 mm for females. Adults of subspecies "obrinus" are on wing in January and from July to November. Adults of subspecies "faventia" are on wing year round, but mainly from June to October and adults of subspecies "lesoudieri" are on wing year round, with no observed peak of abundance.
Blue pigmentation.
Obrina Olivewing butterflies are very unusual because they are one of the few animals with actual blue pigment. Most other species get their blue coloration from a process called coherent scattering, in which scattered light waves interfere to create a blue color. All the other species of "Nessaea" get their blue coloration from the pigment pterobilin. Pterobilin also provides blue for "Graphium agamemnon", "G. antiphates", "G. doson", and "G. sarpedon". Other butterflies in "Graphium" and "Papilio" (specifically "P. phorcas" and "P. weiskei") use the blue pigments phorcabilin and sarpedobilin.