EWING : OBSERVATIONS ON ACRIDID.E. 311 



brainless grasshopper spontaneity persists only to a slight ex- 

 tent. The preening and palp movements, the occasional lifting 

 of the legs of first one side then the other, and the progressive 

 movements of a step or two during twenty-four hours, are ac- 

 tivities produced without any apparent external cause and may 

 be regarded as spontaneous. 



Moreover, Bethe has demonstrated that in brainless arthro- 

 pods the power to inhibit reflex movements is lost. They re- 

 spond to stimuli too slight to elicit reflexes in normal animals, 

 and keep up constant preening and masticating movements and 

 varied activities of the legs ; while some, as for instance the 

 water-beetle, not only retains its progressive locomotor move- 

 ments, but walks incessantly. I observed that the brainless 

 hopper has also lost the power to inhibit reflex movements. It 

 also exhibits the palp and preening movements, as well as the 

 restless lifting of the legs, and responds to the slightest touch 

 by hopping, but it does not make progressive locomotor move- 

 ments of more than one or two steps during twenty-four hours, 

 and its respiratory movements are no longer inhibited when it 

 is first taken in the hand. 



The change in flexion of the legs, followed by the weakened 

 condition of the body, manifested by resting its head against 

 the table, and the quick exhaustion after any effort, indicates, 

 as will be pointed out later, that the brain exercises a control 

 over tension of the voluntary muscles. 



Coordination, however, as well as direction, still persists with 

 the loss of the brain, since the hoppers in walking move their 

 legs in normal order, turn over if placed on their backs, can 

 hop, fly and alight in a normal manner, and move toward the 

 unstimulated side when a leg is pressed. 



II. Removal of Half of the Brain. 

 Extirpating half of the brain, by every operative precaution 

 above spoken of, produced no material change in the respira- 

 tory movements, and the spiracles of both sides moved in the 

 normal member. If the right half, for instance, is destroyed, 

 sensation persists in the left, not in the right antenna, and the 

 abdomen is curved toward the left side. The right walking- 

 legs are flexed, so that the animal stands higher on the operated 

 side, while the right jumping-leg is extended and, in walking, 

 seems to propel the right side of the body onward. The wing 



