I .V s C. L. TUKNKK. 



FIG. 6. Photomicrograph of the last four segments of a mutant larva. The 

 Malpighian tubules are present but as they bear no pigment they do not appear in 

 the photograph. X 21. 



FIG. 7. Photomicrograph of the head of a mutant larva. The ocellus (Oc.) is 

 not pigmented and so does not show in the photograph. X 140. 



FIG. 8. Photomicrograph of the face of a mutant pupa illustrating the com- 

 pound eyes (C.E.) which contain no pigment. X 100. 



FIG. 9. Photomicrograph of the face of a mutant adult showing the compound 

 eyes (C.E.). The margins and the interspaces have a yellowish-brown color that is 

 characteristic of the heavily chitinized parts of the body but there is none of the 

 dark reddish brown pigment in the facets that is found in the facets of the normal 

 fly. X 132. 



FIG. 10. Photomicrograph of an adult mutant fly showing the absence of pig- 

 ment in the compound eyes (C.E.) and in the Malpighian tubules. X 30. 



