NERVOUS SYSTEM OF INSECTS. 



339 



the antennal nerves (Fig. 281, at). Tlie simple brain of the 

 locust may be compared with the more complicated brain of 

 an ant, as seen in Fig. 284. 



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

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



Fig. 284. — ^Right half of an ant's-brain: UG^ infra-cesophao;eal ganglion ; Gr, brain ; 

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

 of tlie brain lyinti next to tile basal portion of the brain, from which the nerves to the 

 pimple eyes {au) arise ; Am, 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 iofra-cesophageal ganglion. — After Leydig, from Graber. 



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

 connected with the supra-cesophageal 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, 



