THE COCKROACH. 



357 



The large tracheae which take their origin from these 

 fetigmata imrneJiafcely divide and give off dorsal and ventral 

 branches ; the former unite in a series of arches on each 

 side of the heart, while, on the ventral side, the branches 

 are connected by trunks which run parallel with the abdominal 

 gano-lia. Large tracheae pass from the anterior thoracic stigma 

 through the neck into the head, and, in the abdomen, the vis- 

 cera receive an abundant supply of air-tubes. 



^-<t-h 



FiGt. iOO.—Bla^ta orlentalis.—C. the brain with the antennary {a) and optic (b) 

 nerves^ ; c, e, f. g. //, ptomato-gastric nerves. B. the anterior cud of the gullet. 

 A, the crop. i>, the gizzard. 



The lobes of the corpus adiposum are also plentifully 

 supplied with tracheoe, while fine trunks enter the substance 

 of tlie ganglia and nerves and there ramify. Tracliere accom- 

 pany the nervures of the wings and are abundantly distrib- 

 uted to the muscles. 



The nervous system consists of the supra-cesophageal 

 ganglia (Fig. 100, ^4), commonly termed the brain, united by 



