Fig. 1. -Aminobutyric acid (GABA) immunostaining in the optic lobe of Leucophaea maderae. (A) Horizontal section through the optic lobe, showing immunostaining in the lamina (La), medulla (Me), accessory medulla (AMe) and lobula (Lo). The arrow points to immunostained accessory lamina at the posterior proximal edge of the lamina. Asterisks indicate a strongly stained layer in the medulla. dist, distal; front, frontal. Scale bar, 100 µm. (B) Superimposed images from two frontal sections through the accessory medulla (AMe) and ventro-median aspects of the medulla (Me). GABA-immunoreactive processes in the distal tract (DT) separate into two fibre bundles (arrowheads) and innervate the noduli of the AMe. The thin black arrows mark primary neurites of GABA-immunoreactive somata. Scale bar, 50 µm. (C) Horizontal view showing the frontal part of the medulla (Me), the accessory medulla (AMe) and the distal tract (DT). A fascicle of immunostained axons leaves the distal tract and enters a strongly immunopositive layer of the medulla (arrow). Scale bar, 50 µm.