ANATOMY AND PHYSIOLOGY 



brain cannot go to its food, though it is able to eat if food be placed in 

 contact with the end-organs of taste, as those 

 of the palpi; furthermore, it walks or flies in an 

 erratic manner, indicating a lack of co-ordina- 

 tion of muscular action. 



The subcesophageal ganglion controls the 

 mouth parts, co-ordinating their movements as 

 well as some of the bodily movements. 



The thoracic ganglia govern the appendages 

 of their respective segments. These ganglia 

 and those of the abdomen are to a great extent 

 independent of brain control, each of these 

 ganglia being an individual motor center for 

 its particular segment. Thus decapitated in- 

 sects are still able to breathe, walk or fly, and 

 often retain for several days some power of 

 movement. 



In regard to the sympathetic system, it 

 has been shown experimentally that the fron- 

 tal ganglion controls the swallowing movements 

 and exerts through the stomatogastric nerve 

 a regulative action upon digestion. The dor- 

 sal [sympathetic system controls the dorsal 

 vessel and the salivary glands, while the 

 ventral sympathetic system is concerned with 

 the spiracular muscles. 



SENSE ORGANS 



FIG. 116. Sympathetic nerv- 



5 



a, antennal nerve; b, brain; /, 

 frontal ganglion; I, I, paired 

 lateral ganglia; m, nerves to 

 upper mouth parts; o, op- 

 tic nerve ; r, recurrent 

 nerve; s, nerve to salivary 



For the reception of sensory impressions glands; st, stomachic ganglion. 



I u ^t. TI - * After KOLBE. 



from the external world, the armor-like integu- 

 ment of insects is modified in a great variety of ways. Though sense 



FIG. 117. Transverse section of an abdominal ganglion of a caterpillar. /, nerve fibers; g, 

 ganglion cells; n, nerve sheath; p, Punktsubstanz. 



