Fig. 11. Pymetrozine was not observed to have effects on central mesothoracic motor control circuits, or on higher control centres, e.g. in the subesophageal ganglion. The response of the extensor (A) and flexor (B) tibiae nerves to ramp-and-hold stimulation of the femoral chordotonal organ (fCO; bottom traces, 240 µm or 40° fCO movement) was examined before and after application of 10^–6 mol l^–1 pymetrozine to the ventral nerve cord, but not to the fCO (hemolymph space of the leg isolated by Vaseline^TM plug (see text). Sample recordings (i and ii) and time histograms (iii and iv) are shown for the intact (control) situation (i and iii) and after pymetrozine application (ii and iv). Bin widths of histograms 10 ms; ordinates normalized to number of stimulus presentations. Different individuals were used in A and B.