FIG. 3.

Formation of labeled acetate after microinjection of H¹⁴CO₃⁻ into the P1 (○), P3/4a (●), and P4b (C) sections of C. orthognathus hindguts incubated under H₂ (Fig. 2B, series 5). Each data point represents an injection into a separate gut. For definitions of the sections, see Fig. 1 in the companion paper (33).