NERVOUS SYSTEM OF INSECTS. 



330 



the antennal 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-oesophageal ganglion (Fig. 283, if], as its name 

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



ati 



Fig. 2&4. Right half of an ant's-brain: W<7, infra-cesophageal ganglion; Gr, brain ; 

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

 of the brain lyin^ next to the basal portion of the brain, from which the nerves to the 

 simple eyes (au) 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-resophageal 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-oesophageal ganglion arise three 

 pairs of nerves, which are distributed to the mandibles, 



