Fig. 4

Selected sagittal and transversal paraffin sections of the synganglion of Notophuga sp. (a–c) and Galeodes turkestanus (d). a, b The arcuate body is located in the posterodorsal protocerebrum. Neuromeres associated with walking legs are separated from the malleolar projections by a thin cortex of somata (compare also d). The malleolar neuropil is located medially in the anteroventral synganglion, close to the pedipalpal neuromere. Note the bundle of malleolar afferent axons (white arrow in b). The projection neuron tract penetrates the cortex (compare also Fig. 2b) of the malleolar neuropil and proceeds dorsad (white arrow in a). c Paramedial section. Note the separation of the ventral fourth walking leg neuromere projection (white arrow) and the dorsal ventral nerve cord. Anteriorly, individual malleolar glomeruli can be distinguished. d Horizontal section of the G. turkestanus synganglion (prosoma midsection). The ventral nerve cord is enwrapped by a contiguous soma cortex, the malleolar projections (white arrow) are ensheathed by a thin layer of somata, embedded in the VNC. Abbreviations: ab arcuate body, co soma cortex, es esophagus, mb mushroom body, mn malleolar neuropil, Pen pedipalpal neuromere, VNC ventral nerve cord, vsN visual nerve