33O STEFAN KOPEC. 



removal of the subcesophageal ganglion would have the same effect 

 as the removal of the brain, as in this case the continuity between 

 the brain and the remainder of the central nervous system is dis- 

 turbed. But the corresponding data of Tables I. and II. prove 

 that in this case the insects behave normally. The behavior of 

 insects which have been deprived of two or three successive ganglia 

 of the thorax or of the abdomen was also similar : both parts of 

 the body, the part situated in front of the place of operation and 

 that behind it, attained the stage of pupation simultaneously, al- 

 though the connection between the central nervous system of the 

 two parts had been quite destroyed. After several trials, I con- 

 vinced myself that processes of regeneration never occur, such as 

 would be able to produce a new nervous communication between 

 the two parts. 



At most it must be admitted that the brain is connected with the 

 part of the nervous system situated behind the place of operation 

 by means of the " intestinal nervous system," which is composed of 

 very small ganglia lying in the tissue surrounding the oesophagus 

 and connected in front with the brain. (The "sympathetic nerv- 

 ous system " of the caterpillar undergoes rupture during the re- 

 moval of the ganglia of the nervous chain. For corresponding 

 anatomical data see the paper of Cattie, '80.) Owing to the un- 

 usually small size of the intestinal system, it was impossible to 

 study it in greater detail by operating. On the other hand, I do 

 not consider it possible that any nervous conduction between the 

 two parts of the larval body operated upon can take place, since I 

 observed several times that the part of the body behind the seg- 

 ment deprived of its nervous ganglion does not respond to any 

 stimuli exerted on the fore-part of the caterpillar operated upon, 

 and vice versa. The fore-segments of the operated body may be 

 sharply pinched, injured, cut, or burned, still the hind part does 

 not perform even the slightest movements referable to the stimuli, 

 although under normal conditions even slight excitations of any 

 part of the body produce violent reflexes. In regard to this, there 

 seems to be no doubt that the fore-part of the body of the operated 

 caterpillars is in no nervous connection with the part situated be- 

 yond the place of operation. It is, therefore, most probable that 

 the brain does not influence the general processes of metamorphosis 



