T. magellanus shows a blue-green sheen if viewed from an oblique angle. Troides magellanus and the much rarer T. prattorum, are noted for their use of limited-view iridescence: the yellow of the dorsal hindwings is modified by bright blue-green iridescence which is only seen when the butterfly is viewed at a narrow, oblique angle. This “grazing iridescence” is brought about through diffraction of light (after back-reflection) by the wings’ extremely steeply-set, multilayered rib-like scales (rather than the ridge-lamellae of most other iridescent butterflies, such as Morpho species). Such limited-view iridescence was previously only known from one other species, the lycaenid Ancyluris meliboeus. In A. meliboeus, however, the iridescence is produced by ridge-lamellar scales and features a wider range of colours.
This butterfly is named for the explorer Ferdinand Magellan who was killed in the Philippines in 1521.