PHB is a set of two ciliated neurons that are components of the phasmid sensilla. Posteriorly directed processes emanate from each cell body in the lumbar ganglia and terminate in a cilium. The basal body of the cilium is dorsal to that of PHA, which is also part of the same sensillum. Anteriorly directed processes enter the pre-anal ganglion via the lumbar commissures and run near the middle of the neuropile for the length of the ganglion (e). The synapses of PHB are generally rather larger than those of PHA. The predominant synaptic output is to AVA and PVC at dyadic synapses (a, b). There are also synapses to AVD (c) and VA12 (b). There are several gap junctions to itself (d) and a small gap junction to AVH. The main synaptic input is from PHA (*c). Magnifications: (a-d) x 25500.
Web adaptation, Thomas Boulin, for Wormatlas, 2001, 2002