NERVOUS SYSTEM OF INSECTS. 



319 



the antennal nerves (Fig. 276, at}. The simple brain of the 

 locust may be compared with the more complicated brain of 

 an ant, as seen in Fig. 279. 



The infra-cesophageal ganglion (Fig. 278, if), as its name 

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



Fi& 279. Right half of an ant's-brain: (7, infra-cesophageal ganglion; Or, brain; 

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

 of the brain lyins; next to the basal portion of the braiu, 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 wi:h the iufra-cesophageal ganglion. After Leydig, from Graber. 



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

 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. 



