Indian Journal of Scientific Research

The nervous system of Halys dentatus F. exhibits a great degree of consolidation. It consists of a compact brain and two ventral ganglia situated in the thoracic region. The brain consists of the proto-, deuto - and tritocerebrum and gives out respectively, a pair of optic and ocellar nerves, a pair of antennal nerves and a pair of short thick fronto-labral nerves. The sub-oesophageal ganglion is inconspicuous and is connected to the brain by short circum-oesophageal connectives. The fusion between the two is so compact that the whole structure appears to be a single solid mass.. Three pairs of nerves mandibular, maxillary and labial arise from sub oesophageal ganglion and innervate the muscles in the respective areas. The first ventral ganglia (prothoracic ganglion) are situated in the prothorax. It gives out two pairs of nerves which innervate the prothorax. The second ganglia (thoracic ganglionic mass) lie in the mesothorax and are formed by the fusion of meso, metathoracic and all abdominal ganglia. It gives out two pairs of nerves to mesothoracic and two pairs in metathoracic regions. The ventral longitudinal nerve, which connects the sub-oesophageal, prothoracic and the thoracic ganglionic mass, are completely obliterated due to shifting of the ganglionic centres and their fusion. The abdomen is innervated by unpaired median abdominal nerve and three pairs of segmental abdominal nerves which innervate the muscles and all other visceral organs in the respective segment. The course and termination of nerves of different ganglionic centres have been traced to terminal ends.