196 SELF-WROUGHT AIDS TO MOTION. 



which direct it, there is matter for thought, and doubt, and 

 discovery ! 



Another peculiarity distinguishes the movements of some 

 insects from those of nearly all other animals save man. This 

 is their power, in some instances, of constructing and availing 

 themselves of what may be called artificial helps. Such are 

 the aerial bridges of silken thread, and the balloons of flake, 

 by which aeronautic spiders cross a void or ascend to the 

 clouds. Such the silken ropes, descending or mounting by 

 whose aid a variety of caterpillars, especially the Loopers, are 

 enabled to break their falls from, or resume their positions 

 upon, elevated stations ; and also of this description are the 

 rope-ladders, spun of the same material and employed by the 

 devouring crawler of the cabbage to scale a garden wall, or, 

 if we please to test her ingenuity at efforts for escape, the 

 smooth perpendicular of an imprisoning glass. 



The above, and all other insect movements, are, of course, 

 to be observed at various times and seasons; but the subject 

 of animal motion harmonizes not amiss with this present 

 month of November, as well as with the two which have gone 

 before it, for to all three appertain strong and strongly-working 

 features of external movement preceding and preparatory to 

 the external fixedness of winter. 



In September, the winds, usually hushed in August, uplift 

 their uproarious voices in the equinoctial gales. The birds, 

 lately so mute, resume their music to lament the departure, as, 



