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-<Bsophageal ganglion (Fig. 278, ?"/"), as its name 

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



ati 



l 



Fig:. 279. Right half of an ant's-brain: nG, infra-oesophageal ganglion; Or, brain ; 

 (?, central connective portion-* ; W, semi-circular bodies of the small-celled portion 

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

 simple eyes (aw) arise ; Au, optic lobes ; An. antennal lobes (the bodies appearing 

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

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

 the brain with the int'ra-cesophageal 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-oesophageal ganglion arise three 

 pairs of nerves, which are distributed to the mandibles. 



