

OGY. 



<fiw. "J >f the m I, as 



.v.glion in the head above the ies<>ph- 



mcnt of 



on the floor of the ivity, and connected 



iinal cords. In the head, one of th -on 



the (.esophagus, from the brain to another ganglion in 



the head below the < esophagus, thus forming a nervous collar about 



the alii:. anal. Fn>n: ..inglion nerves arise, which sup- 



ind from the thoracic ganglia nerves extend 

 I'his scri nglia is really a double one ; 



but each pair of ganglia are mor closely united on the mid- 



tile line of the bod)', and often appear as a sin- 

 gle ganglion. Fig. 44 gi\ neral vu 

 the nervous system of Corydalus cornut: 

 represented by Leidy. From the brain (a 

 large nerves extend to the compound 

 and a smaller pair to the antenna,- ; the sub- 

 cesophageal ganglion (b) supplies the mouth- 

 parts with nerves ; and each of the thoracic 

 and abdominal ganglia supplies its segment of 

 the body. 



In Corydahis ' Fig. 44) the eighth and ninth 

 pairs of abdominal ganglia are united, and 

 drawn cephalad into the seventh abdominal 

 segment. The same thing is presented by 

 irva of Cossns (Plate I., 10). This is an 

 illustration of what has been termed ceph- 

 alization of the nervous system. In the adults 

 of insects of the higher orders this cephalixa- 

 tion of the nervous system is carried to a 

 gn nt. In son: the abdominal 



a common mass and drawn cephalad into the 



:. Between this and the form presented by C^rydnlus 



With the higher insects the nervoi :n un- 



d changes during the life of the individual. In a 



illar it is of the form shown in Plate I.; in the pupa state 



-.-.hat shortened; and in the adult the abdominal 



ill united with the thoracic '-.aiiglia into a 



us system of 



Corydalui. 



See figures by Newport, ( -.II. pp. '/>3-</>5- 



