Occurence of pterin pigments in hymenoptera

It has been found that pterins exist in tissues of animals belonging to nearly all groups; their occurrence as pigments, however, is restricted to insects and cold-blooded vertebrates. Among Lepidoptera, they are always present in the wing-scales of the Pieridæ and appear to be a biochemical characteristic of that natural family. Becker and Schöpf and Becker also found pterins in the integument of Hymenoptera and gave evidence of their wide distribution within this order