Page:Jardine Naturalist's library Entomology.djvu/185

Rh ganglia are nearly united into one mass; and all the nerves furnished by these ganglia to the locomotive organs, will be seen to have acquired a considerable development. The sympathetic nervous system has been known from the time of Swammerdam, who discovered it in the larva of the rhinoceros-beetle (Oryctes Nasicornis,) but its real nature, and the analogy it bears to the great sympathetic nerve of the vertebrata, were not understood till it was made the subject of a special investigation by John Müller. It exists more or less distinctly in all articulated animals, but in none is it so complete as in insects. It is considered as forming two divisions; one of them consisting of a single cord, running along the anterior portion of the alimentary canal, and emitting delicate filaments on each side; the other of a double nervous web, originating on each side by one branch from the posterior portion of the anterior cephalic ganglion, running down the esophagus, and sending forth branches to the single nervous cord. Both these divisions stand in the most intimate relation to each other, and form one continuous system. The first is most conspicuous in Coleoptera, Neuroptera, and Lepidoptera. In these it takes its rise in two arched branches from the anterior cephalic ganglion, which unite in the centre and form a small knot, from which a single nerve emanates and runs beneath the cerebrum. From its curved shape, this was called by