Biochemistry of Locusts

migratoria migratorioide8 R. & F.) and in the eyes of Dro8ophila melanoga8ter (wild) andEphe8tia kilhniella have been investigated. 2. The pigments cannot be distinguished from each other. As the redox pigments reported in other insects also appear indistinguishable from our pigment, it is proposed that this widespread insect pigment be termed insectorubin. 3. Insectorubin has been isolated as a reddishbrown powder which quickly changes into an intractable dark-brown powder, reminiscent of melanin; its properties have been fully recorded. 4. It is extremely resistant to normal methods of chemical attack, but it has yielded two pyrrole derivates. These have not been unequivocally identified but appear to be N-methylpyrrole and haemopyrrole. 5. Insectorubin is the pigment responsible for the colour ofthe pink faeces produced by starved locusts and of the pink patches in the subcutaneous tissue and integument ofLocusta infected with Pli8tophora. 6. Spectral data on the colours produced by a number of indole and pyrrole derivatives with Ehrlich's diazo reagent are recorded.