The cercal receptor system of the praying mantid, Archimantis brunneriana Sauss. II. Cercal nerve structure and projection and electrophysiological responses of the individual receptors.

The bilaterally paired cercal nerves of Archimantis brunneriana Sauss. leave the terminal ganglion posteriorly and then turn dorsally through muscles at the rear of the abdomen to enter the cerci, where each splits into two branches; successive branchings occur further distally in each cercus. In the distal nerve branches large axons tend to be grouped together. The cercal nerves are heavily wrapped in glial sheaths. Cobalt backfills of the cercal nerve reveal a projection which enters the ganglion at approximately 30 degrees to the midline and then turns parallel to it. Most of the projection remains ipsilateral but bundles of axons approach or cross the midline in 6-8 places. At the anterior end of the ganglion there are strong projections both laterally and medially. In the posterior half of the ganglion fibers run ventrally to surround two glomeruli and there is a dorsal projection in the anterior half of the ganglion. There is a strong projection anteriorly into the ventral nerve cord. The electrophysiological responses of single cercal receptors to pulses of wind were recorded in the cercal nerve or terminal ganglion. These receptors, presumed to innervate filiform hairs, were then filled with Lucifer Yellow. All had ipsilateral projections. Most receptors showed little adaptation to stimuli as long as 5 seconds.