316 KANSAS UNIVERSITY SCIENCE BULLETIN. 



third leg produces responses only from these, and fluttering 

 of the wings and wing-covers. 



When the second thoracic ganglion is removed, there is a de- 

 crease in the rate of respiratory movements, loss of motion in 

 the second thoracic spiracle and of sensation and motion in the 

 second pair of legs, and loss of the power of flight. The 

 animal hops and walks, but does not move the second pair of legs. 

 It tries to turn over if placed on its back, but cannot without 

 its front and jumping-legs. If the antennae are pinched it uses 

 its front leg to push away the forceps ; if the hind legs are 

 pinched it does not push away the forceps, but hops away. 

 Faivre found that the respiratory movements in the water- 

 beetle ceased upon removal of the meso-thoracic ganglion, and 

 only reappeared upon stimulation, and then only when the 

 meta-thoracic ganglion was still intact. My results do not 

 agree with this, since I found that respiratory movements con- 

 tinue without stimulation after extirpation of this ganglion, 

 and the respiratory movements of the abdomen are not greatly 

 changed by the simultaneous removal of this and the meta- 

 thoractic ganglion. 



After extirpation of the third thoracic ganglion, only the rate 

 of respiration is affected. Motion and sensation in the third 

 pair of legs are lost, as is also the power of flight. The third 

 thoracic spiracle is inactive. The insect turns over when 

 placed on its back. When the abdomen is pinched the legs 

 remain inactive. It can still make progressive movements with 

 its two pairs of walking-legs. 



The air sacs in the thoracic region, even after removal of all 

 the thoracic ganglia, continue to expand and contract with the 

 movements of the abdomen and independently of the thoracic 

 spiracle movements. 



VI. Removal of Abdominal Ganglia. 



The abdominal ganglia are extirpated from the ventral side 

 of the body by removing a small piece of chitin that lies di- 

 rectly over the ganglia. They were destroyed with a hot needle 

 or extirpated with bent scissors or hooked scalpel. The wound 

 was covered with shellac. 



When the first abdominal ganglion is destroyed there is a 

 loss of motion in the first abdominal segment and its spiracles, 

 but all remaining parts of the body continue actively in the 



