Fig. 6. Light micrograph of the anterior portion of a T-1 follicle from a stage-9 ovariole with corresponding extracellular H⁺ fluxes superimposed. Additional measurements near the H⁺ efflux along the T-1/T-2 junction reveal that the efflux extends to the anterior pole of the T-1 follicle (asterisk). These follicle cells presumably are also involved in interfollicular stalk morphogenesis, and will ultimately form the columnar cells at the anterior pole of the follicle. Red scale bar, 100 fmol cm^–2 s^–1; black scale bar, 100 µm.