The Vibration Line

 Spiders do not always stay on their webs.  Some species do but most like to lie in a secluded place during the day.  But, if they stay off their webs all day they wont be able to eat.  That would be the case if God hadn't had another plan.  The spider sits in a little out of the way place and rests all day, but it's leg is touching a cord.  This cord is attached to the middle of the web where it can pass on vibrations to the spider.  If the spider feels the cord move it will shimmy down the line to the web where it will grab its prey and stab it and then carry it back to it's lair and eat it. 

   Fabre tried some experiments with the line.  He cut the line and put a live bug on the web to see if the spider would still come.  The spider did not come until nightfall when it came to its web and devoured its prey.  And thus we see the spider knows the prey is there only by the cord, not by eyesight.