This is one of my favourite species from Central America, Costa Rica The green indeed is stunning but the blue colour is something very unique. This is one of the species that produces blue pigment so the colour is not effect of refracting light which pass thru the scales as this is the case in 99.9% of other species.
Quick update, the pigment is called pterobilin. It is also synthesized in a few other species but does not accumulate as much as in Nessea. The other species are Graphium sarpedon (bluebottles); Graphium agamemnon, Graphium antiphates, and Graphium doson. There is other blue pigments like sarpedobilin and phorcabilin but they are not as blue as pterobilin.