rc1/rc1 normal; in lys1 rc1/lys1 rc1, fat cells of head and thorax acquire brownish red pigment. Effect most prominent in one or more rows of pigmented cells along mid-dorsal line of thorax just beneath chitin. Pigment is ommochrome since lys1 rc1 bw1 cells are pigmented, whereas v1; lys1 rc1 cells are colorless except in kynurenine-fed flies. RK3.