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The histomorphology of the retrocerebral endocrine organs of the larva of the lemon-butterfly, P. demoleus has been described employing a conventional neurosecretory staining technique. The larval organs lie a little away from the brain and oesophagus and, therefore, are not sub-aortic in position unlike most other insects and the adult of this species itself. There are two long NCCs which innervate other target organs in addition to the CC. The recurrent nerve of the stomatogastric nervous system retains its normal connections with the CC even in absence of the hypocerebral ganglion. Histological evidence suggests that the NSM inside the CC remains intraaxonal without being possibly unloaded in the substance of these organs. Axonal transport of NSM to target organs is also in evidence and though NSM is seen in the NCA, it could not be detected inside the CA.

Unlike many heteropterans, the retrocerebral endocrine organs of the water-bug, Sphaerodema annulatum are not fused with each other or with the hypocerebral ganglion. The NCC I bypass the CC and also innervate the oesophageal dilator muscles, CA and post-allatal pericardial cells in addition to aorta. Terminall, this nerve dilates into an ampulla showing accumulation of NSM and, therefore, regarded as a transitory storage centre. Each CC is divisible into two histological halves; the anterior half being negative and the posterior half positive to AF. The CA are innervated by two NCAs one of which (the NCA I) ramifies to form a NSM containing nerve-net on the surface of the gland regarded as another transitory storage centre. Three qualitatively different secretory factors are recognised in the retrocerebral endocrine-aortal complex of this insect -- of which one, localised in the posterior half of the CC, is regarded as indigenous and the other two present in the CA, aorta and pericardial cell nerves as cerebral in origin. Of the latter, both the factors are transported to the CA while only one to the aorta and pericardial cell nerves.