[On the function of thealb-locus in the final synthesis of ommochromes inEphestia kühniella Z.]

1. Metabolites of the tryptophan→ommochrome pathway were examined in adults of the mutantalb ofEphestia. The mutantwa and the wild type were analysed for comparison. The investigation was restricted to head and ovary. 2. In thealb head, the concentration of 3-OH-kynurenine was more than three times higher than that in the wild type head. The quantity of ommochromes inalb heads is reduced to 1% of that in the wild type, but the ommochrome spectra are identical. Thewa head fails to accumulate demonstrable amounts of any of the analysed metabolites. 3. The ovaries of all three strains contain identical concentrations of 3-OH-kynurenine. Ommochromes are absent from this organ. 4. The results indicate that different mechanisms for the accumulation of 3-OH-kynurenine may exist in different tissues.