108 ZOOLOGY. 



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

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

 extends bacli to the end of the body. 



Fia. 132.— A Carabus beetle in the act of walking or running:. Three legs (L' 

 /?", L') are directed forward, wliile the others iJS', L', /), which are directed 

 backward toward tlie tail, have ended their activity, a 6, c d, and e f are 

 curves described by the end of the tibi,i< and passing back to the end of the 

 body; 6 A, d i, and/ 9 are curves described by the same legs during their 

 passive change of position. 



All insects breatliG by means of a com plicated system of 

 air-tnbes ramifying throtigliout the body, the air entering 

 through a row of siiiracles or breathing-holes {stiginata) 



