EWING : OBSERVATIONS ON ACRIDID^. 315 



position of the stick. In standing, it may incline more to one 

 side, and often remains in any position in which it has been 

 placed ; as, for instance, the thorax touching the table and the 

 abdomen and jumping-legs raised far above it. 



It makes purposive reflex movements, though these are not 

 as strong as in the normal hopper, and the power of localization 

 is still left. If any part of the body easily reached by the feet 

 is touched, they attempt to push away the offending object, 

 for instance, if the posterior part of the abdomen is touched 

 with a pencil, first one then the other leg tries to push away 

 the pencil. If the insect is held with the fingers, it struggles 

 to free itself, and, as in the case in the normal hopper, both the 

 abdominal and thoracic spiracles and the abdominal respiratory 

 movements are increased in rate and force. During the first 

 hours it moves, hops and flies spontaneously ; that is, without 

 any apparent cause. These movements may be due to opera- 

 tive disturbances. The egg depositors open and close rhyth- 

 mically and foeces are often excreted, and it often sways from 

 side to side while standing. 



The results obtained from this experiment corroborate, in 

 many respects, those already cited. This method of removing 

 the suboesophageal ganglion is very simple and satisfactory, 

 from the fact that all of the ganglion is removed. 



Y. Removal of Thoracic Ganglia. 



The thoracic ganglia are easily exposed on the* ventral side. 

 The first is covered by a chitinous plate lying between the first 

 pair of legs. It is successfully destroyed with a hot needle, or 

 can be cut out with a very fine hooked scapel or bent scissors, 

 and the wound covered with shellac. After the shock effect 

 produced by the operation has passed off, the respiratory move- 

 ments of the abdomen and spiracles continue at about half of 

 the rate observed before the operation. There is, however, 

 complete loss of motion of the first thoracic spiracles, as well as 

 loss of motion and sensation in the first pair of legs. It flies, 

 hops and walks with its second and third pairs of legs, and 

 with the aid of these turns over when placed on its back. 

 Evidently the centre for the turnover reflex is not located in the 

 prothoracic ganglion, as Faivre believed it to be in the water- 

 beetle. When the antennae are pinched there are no responses 

 in the walking-appendages, and pinching either the second or 



