FIGURE 1.

Black feces excreted by silkworm larvae. A, V-3 silkworm larvae, black feces, and mulberry leaves. B, morphology of black feces excreted by feeding-stage larvae (V-3) and that of green feces excreted by wandering-stage (W) larvae. The mulberry leaf fragments were black (b) or green (d) in the corresponding black (a) or green (c) feces. C, morphology of the gut dissected from a V-3 silkworm larva, and its gut content from the corresponding location. The midgut is equally divided into three parts (MG1, MG2, and MG3). The hindgut is divided into two parts due to its different morphology (HG1 and HG2). The HG2 content was black. FG, foregut; MG, midgut; HG, hindgut; PY, pylorus.