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 vertebrates1,2. Among Lepidoptera, they are always present in the wing-scales of the Pieridae and appear to be a biochemical characteristic of that natural family3,4. Becker and Schopf5 and Becker6 also found pterins in the integument of Hymenoptera and gave evidence of their wide distribution within this order.