NERVOUS SYSTEM OF INSECTS. 



339 



the anfcennal nerves (Fig. 281, at}. The simple brain of the 

 locust may be compared with the more complicated brain of 

 an ant, as seen in Fig. 284. 



The infra-cesophageal ganglion (Fig. 283, if), as its name 

 implies, lies under the oesophagus at the base of the head, un- 



aii 



Fig. 284. Right half of an ant's-brain: UG, infra-cesophageal ganglion ; Gr, brain ; 

 C, central connective portions ; W, semi-circular bodies of the small-celled portion 

 of the brain lying next to the basal portion of the brain, from which the nerves to the 

 pimple eyes (an) arise ; Au, optic lobes ; An, antennal lobes (the bodies appearing 

 like cells are rounded masses of the network of the substance of the cord ; r, cellu- 

 lar cortical substance of the brain ; ko, twofold body of the commissure connecting 

 the brain with the infra-03sophageal ganglion. After Leydig, from Graber. 



der a bridge of chitine, and directly behind the tongue. It is 

 connected with the supra-oesophageal ganglion by two com- 

 missures passing up each side of the oesophagus. From the 

 under side of the infra-cesophageal ganglion arise three 

 pairs of nerves, which are distributed to the mandibles, 



