THE CEPHALIC GANGLIA. 



607 



plishments of insects by those who have been close observers of their 

 habits. 



Dr. Laycock remarks, when speaking of the cephalic ganglia of insects 

 (Med. Chir. Rev., July, 1853) : " On what structures de- instincts of in- 

 pend, if not on these cephalic ganglia, all those wonderful Jj^? ^hanc" 

 instincts which mimic in their operation the arts of man? ganglia. 

 There is hardly a mechanical pursuit in which insects do not excel. They 

 are excellent weavers, house-builders, architects. They make diving- 

 bells, bore galleries, raise vaults, construct bridges. They line their 

 houses with tapestry, clean them, ventilate them, and close them with 

 admirably-fitted swing-doors. They build and store warehouses, con- 

 struct traps in the greatest variety, hunt skillfully, rob, and plunder. 

 They poison, sabre, and stab their enemies. They have social laws, a 

 common language, divisions of labor, and gradations of rank. They 

 maintain armies, go to war, send out scouts, appoint sentinels, carry off 

 prisoners, keep slaves, and tend domestic animals. In short, they are 

 mentally a miniature copy of man." 



The surprising character of some of these facts might disappear were 

 we acquainted with what may be termed the spring of the action. It 

 has been said by Dr. Whateley that the building of a comb is like the 

 provisioning of a city, in which, through the desire of the dealers to get 

 wealth, is solved what is probably the most intricate of social problems. 

 It is done by no design of theirs, and yet they advance to it as if im- 

 pelled by gravitation or some other insuperable force. A printer may 

 put types together to get money without ever troubling himself about 

 the diffusion of knowledge. A bee may find gratification in what he is 

 doing without any concern about the final use of the comb. 

 Of the cephalic ganglia spoken of in the preceding paragraphs, Fig. 

 295 is an illustration from Mr. Newport, in the case of 

 the imago of the Sphinx ligustri : <z, cephalic ganglia ; , 

 , eyes ; <?, anterior median ganglia ; d, d, posterior lat- 

 eral ganglia of the stomato-gastric system ; Nervous system 

 e,f, large ganglionic masses in the thorax, f insects, 

 giving nerves to the legs and wings. It is Fig. 296. 

 to be understood that upon these ganglia 

 the voluntary action of insects depends. 

 They are the places of reception of the im- 

 pressions on the organs of special sense and 

 cephalic ganglia, the seat of memory. The automatic or in- 

 voluntary apparatus is in part seen at Fig. 296, which is the 

 thoracic portion of the nervous system of the pupa of the same 

 insect : <z, #, c, three ganglia of the ventral cord ; d, d, their 



Thoracic portion 



connecting trunks; e, , respiratory ganglia. The entire of ventral C0 rd. 



Fig. 295. 



