108 
ZOOLOGY, 
agus, whence its name, supra-oesophageal ganglion. From the hrain 
arise the nerves to tlie eyes and feelers, and from it the nervous cOrd 
extends back to the end of tlie body. 
Fig. 132.— a Carabus beetle in the act of walking or running. Three legs (L^ 
L'^) are directed forward, while the othei s (A'^ L"^, /), which are directed 
backward toward the tail, have ended their activity, a b, c d, and e / are 
curves desci'ibed by the end of the tibiae and passing back to the end of the 
body ; 5 /i, d and f g su e 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 body, the air entering 
through a row of spiracles or breathing-holes {stigmata) 
