Fig. 1. Composite camera lucida drawing of PRXamide-like immunoreactive cells and processes in the central nervous system of R. prolixus. Left, dorsal view; right, ventral view. Filled cells indicate strong PRXamide-like immunoreactivity (PRXa-LI) and open cells indicate weak PRXa-LI. Within the mesothoracic ganglionic mass (MTGM), the ventral paired median cells give rise to immunoreactive processes which project dorsally and then exit the CNS via the second, third and fourth abdominal nerves (ABN) where they develop neurohaemal sites. PRO, prothoracic ganglion; SOG, sub-oesophageal ganglion. Scale bar, 200 µm.