THE NERVOUS SYSTEM 



223 



ing more exclusively both of sensory as well as motor ganglia and 

 their nerves, it should be borne in mind that the suboesophageal 

 ganglion also receives nerves of special sense, situated on the palpi 

 and on the tongue, as in the bee 

 and other insects ; hence this 

 ganglion is probably complex, 

 consisting of sensory and motor 

 cells' The third thoracic gan- 

 glion is also, without doubt, a 

 complex one, as in the locusts 

 the auditory nerves pass into it 

 from the ears, which are situated 



oe 



-Hbr 



hup 



FIG. 241. Section through the head of 

 Machilis, showing the braia (br), and sub- 

 oesophageal ganglion (soe. g) ; cl, clypeus ; Ibr, 

 labrum ; oc, ocellus. 



.2 *". j= 1= a 



! 



~~|.o pS 



5 -^ ~ c 



Kfjm Cfi 



5 f |f S3 



v a* /. r 



5 2 = ? a a 



. ^- .2 f 1> P 



ij;ifi*t 



3 *-> O> JZ c i 



03 w tf ^ -^ O 



? ^ ? *- S i 





s = 



^ -^ ci ^ *"" ,s " 

 "^'o; fci^J::"*^ ^- 





. 



s =,=: c 



at the base of the abdomen, while 

 in the green grasshoppers, such 

 as the katydids and their allies, 

 whose ears are situated in their 

 fore legs, the first thoracic gan- 

 glion is a complex one. In the 

 cockroach and in Leptis (Chry- 

 sopila), a common fly, the caudal 

 appendages bear what are prob- 

 ably olfactory organs, and as 



these parts are undoubtedly supplied from the last abdominal gan- 

 glion, this is probably composed of sensory and motor ganglia ; so 

 that we have in the gauglionated cord of insects a series of brains, as 

 it were, running from head to tail, and thus in a still stronger sense 



