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The neuroendocrine system of the homopteran, Idiocerus atkinsoni has been described, employing a neurosecretory stain. Two groups of medial neurosecretory cells (NSC) of one tinctorial type are present in the pars intercerebralis of the brain. Processes believed to be dendrites of the neurosecretory neurons lie superficially underneath the neurilemma and enclose neurosecretory material (NSM). Both the nervi corporis cardiaci, NCCI and NCCII, are branched. The branches of the former join to form an oesophageal nerve that runs on the oesophageal surface and terminates on the midgut, and those of the latter, innervate the oesophageal dilator muscles. Besides being present in the dendrite-like processes and NSC, the NSM is also seen in the NCCI, anterior part of the aorta and oesophageal nerve but not in the NCCII, corpora cardiaca (CC) and the corpus allatum (CA). It is suggested that the release of NSM into the circulation in this insect occurs through two main routes: the dendrites and the aorta. The evolution of the aorta as an exclusive neurohaemal organ in Hemiptera is discussed.