418 MR. NEWPORT ON THE NERVOUS SYSTEM OF THE SPHINX LIGUSTRI. 



that it is by an elongation forwards and outwards in every direction, — by the approxi- 

 mation of nervous trunks already formed, — and by the interweaving, exchange, and 

 recombination of filaments into new trunks, that the development of the nervous 

 system in insects is completed. 



Description of the Plates. 



Plate XIII. 



Fig. 1 . Nervous system of Sphinx ligustii, as seen in the pupa state in the month 

 of April, exhibiting the relative situation of the nerves and ganglia, and 

 the manner in which they are distributed to, and pass under the longitu- 

 dinal muscles. 

 A. A portion of the exterior of the dorsal surface of the pupa case, reflected 

 to show the muscles and nerves. Magnified 2J diameter. 

 Fig. 2. The cerebral and thoracic ganglia and nerves, magnified ten diameters. 

 The letters of figg. 1. and 2. correspond with each other. 



A. Cerebral ganglia. 



B. Optic nerves developing. 



c. Nerves which connect the anterior lateral ganglia with the antennal nerves. 



D. The nerves to the antennae. 



E. The vagus or pneumogastric ganglion and nerve. 



a. Anterior lateral ganglia. 



b. First series of respiratory nerves. 



c. Pair of small nerves from the cord. 

 2 . Second ganglion of the cords. 



d. Nerve to first pair of legs. 



e. Second respiratory nerves. 



/3. Double-rooted nerve to first pair of wings. 



g. To second pair of legs. 



h. Third respiratory nerves. 



i. To second pair of wings. 



k. To third pair of legs. 



/. Nerves of fifth ganglion, which sends branches to the dorsal muscles of 

 eighth segment. 



m. Nerves from the sixth ganglion. 



n. Symmetrical nerves, which, after passing under the longitudinal abdomi- 

 nal muscles, pass up to the dorsal, 

 o, o, 0, 0, 0. Respiratory nerves of the abdomen. 



