The butterfly genus that includes the famous iridescent blue morpho butterflies is Morpho.
Morpho butterflies are neotropical brush-footed butterflies found mainly in Central and South America. Several species have brilliant blue wings, including Morpho menelaus and Morpho helenor. Their color is not produced simply by blue pigment. Microscopic structures in the wing scales reflect particular wavelengths of light, creating structural coloration.
The blue appearance can change with viewing angle because reflected light is directional. The undersides of many morpho wings are brown and patterned, providing camouflage when the insect is resting with its wings closed. This contrast helps explain why a morpho can appear dazzling in flight but difficult to see when settled.
“Morpho” is a genus name, not the scientific name of one single blue species. Blue morpho is a common name used for several closely related species, so a question about the group is best answered with the genus Morpho.