318 KANSAS UNIVERSITY SCIENCE BULLETIN. 



meats in the grasshopper. Each ganglion of the thoracic and 

 abdominal ventral cord is the centre for respiratory movements, 

 and reflex actions of the segment and the appendages to which 

 it belongs. Not only the whole abdomen, but different seg- 

 ments of it will continue their respiratory activity when severed 

 from the body. 



2. The posterior part of the brain exerts an inhibitory power 

 over the anterior part of the grasshopper's brain. The anterior 

 part of the brain is the seat for spontaneous progressive loco- 

 motion. If the posterior part of the brain is destroyed, leaving 

 the anterior strip of the brain tissue in tact, the animal mqves 

 incessantly. If, however, the whole brain is destroyed, the 

 grasshopper stops its progressive movements almost entirely ; 

 it takes only a step or two in twenty-four hours. 



3. The brain of the grasshopper is the centre for swallowing 

 movements and for inhibiting reflex movements. With the loss 

 of the brain, the animal neither moves its mandibles nor swal- 

 lows food, and it now responds to subnormal stimuli in an ex- 

 aggerated way by hopping or flying. Moreover, the palp and 

 preening movements, as well as the rhythmical lifting of the 

 legs are of frequent occurrence, and for no apparent cause. 



4. The grasshopper's brain is not the centre for coordinate 

 movements and direction. Since, when its brain is removed, 

 the insect will respond when stimulated by walking, flying, 

 hopping and righting itself in a normal manner, and will, 

 moreover, move in a direction away from the irritating cause. 



5. The brain controls the tonus of the muscles, since after its 

 extirpation, although the grasshopper makes purposive move- 

 ments to defend itself, it does not do so nearly so powerfully as 

 does the normal animal, and it is very soon fatigued. The po- 

 sition of the head and appendages is altered when the brain is 

 destroyed. The head droops, the flexor muscles of the legs con- 

 tract, so that the appendages are at first strongly flexed and then 

 extended beyond the normal, due possibly to the contraction 

 of the extensors or inhibition of the flexors. The influence ex- 

 erted by the brain over the tension of the voluntary muscles is 

 also illustrated by the position of the legs and body, as well as by 

 the direction of progressive movements, when half of the brain 

 is extirpated. During a definite period of time the hopper then 

 inclines more to the side, and moves in a circle toward the un- 



