Fig. 4

General anatomy of protocerebrum and visual neuropils (Richardson (Platybunus pinetorum) and Wigglesworth stains (Leiobunum spec.), dorsal is up). a transversal section showing eye nerve, first and second visual neuropil with border in between (arrowhead). Bar 100 μm. b sagittal section showing eye nerve, first and second visual neuropil with border in between (arrowhead); note eye nerve separating in several bundles after entering brain (arrow). Bar 100 μm. c transversal section with eye nerve, first visual neuropil and on right hemisphere beginning of second visual neuropil; note second neuropil darker stained. Bar 100 μm. d seven sections after C; first and second visual neuropil with border in between (arrowhead). Bar 100 μm. e 16 sections after D; arcuate body in dorso-posterior position; note arcuate body darker stained. Bar 100 μm. f sagittal section with first visual neuropil in anterodorsal position and arcuate body in dorso-posterior position; note arcuate body darker stained. Bar 100 μm. g four sections after F; first and second visual neuropil in anterodorsal position with border in between (arrowhead) and arcuate body in dorso-posterior position in close vicinity to second visual neuropil; note second visual neuropil and arcuate body darker stained. Bar 100 μm. h three sections after G; second visual neuropil and arcuate body contact each other. Bar 100 μm. AB, arcuate body; EN, eye nerve; M, median eye visual neuropil