( 356 ) 



Chapter XV. 



Peculiar Motiom of Insects. 



Nothing that has life seems capable of existing long 

 without motion. The oyster fixed upon the rock must 

 open and shut its shell, and the most gnarled oak must 

 wave its branches, otherwise their fluids will stagnate, 

 and disease will ensue. In our own case, we cannot, 

 if we would, put a stop for any length of time to all 

 our motions. We have the power,- indeed, of inter- 

 rupting the nictitation of the eyelids ; but if we keep 

 our eyes fixed for a few minutes they become dry and 

 painful for w-ant of the regular supply of moisture 

 spread over them by the process of winking. Breath- 

 ing, again, being a more important operation, cannot 

 be long interrupted, without serious consequences; 

 and when the motion of any of the limbs is prevented 

 by the accidental injury of its joint, it usually shrinks 

 and dwindles into less than half its natural magnitude, 

 because the proper quantity of the nutritive fluids is 

 not impelled thither in consequence of its deficiency 

 of motion. 



We have already seen how indispensable the mo- 

 tions of insects are to the due expanding of their 

 wdngs upon emerging from the pupa state; and 

 several remarkable circumstances show that, inde- 

 pendent of change of place in search of food or of 

 other localities for their progeny, motion is necessary 

 to their well-being. At least there does not seem 

 any other plausible explication of what we may term 

 stationary motions. Kirby and Spence's "motions 

 ot insects reposing,"* appears to be a phrase which 

 would not apply, for example, to an ox chewing the 

 cud, or a cat washing her face with her paw, — mo- 

 tions jneciselv similar to many of those cf insects 

 * Indod. vol. ii. p. 304. 



