108 



ZOOLOGY. 



agus, whence its name, supra-oesophageal ganglion. From the brain 

 arise the nerves to the eyes and feelers, and from it the nervous cord 

 extends back to the end of the body 



Fig. 132— a Carabus beetle in the act of walking or running. Three legs (L 1 , 

 i? 2 , L a ) are directed forward, while the others (A' 1 , L 1 , /), which are directed 

 backward toward the tail, have ended their activity, a ft, c d, and e /are 

 curves described by the end of the tibiae and passing back to the end of the 

 body; 6 h, d i, and/ g are curves described by the same legs during their 

 passive change of position. 



All insects breathe by means of a complicated system of 

 air-tubes ramifying throughout the bod}', the air entering 

 through a row of spiracles or breathing-holes {stigmata) 



