The Structure and Habits of Spiders. 77 



The spider begins to cross them with adhe- 

 sive threads near the end of the upper ray at S'. 

 After fastening the end of the thread, she walks 

 along toward the centre, scratching away all 

 the time with her calamistrum, till she comes to 

 a place, 5, where she can cross to the next ray. 

 She crosses over, and goes outward toward S", 

 the thread shrinking as she goes, until, when 

 she arrives at S", it is just long enough to reach 

 across to S'. She fastens it by laying it along 

 the ray for a short distance, and goes inward 

 again till she reaches 7, where she crosses to 

 the next ray ; and so on till the thread is fin- 

 ished to S"". Here she stops spinning, and 



goes up the lower ray to A, and along the 







upper one to 4, where she starts another cross- 

 thread. This goes on till the whole web is 

 filled, as in Fig. 39, nearly to the centre. 



When the web is finished, the spider goes up 

 the thread A o, to within an inch or so of the 

 twig to which it is fastened ; turns round, and 

 takes hold of the thread with her front-feet ; 

 then pulls herself backward with her hind-feet 

 up to the twig. She thus tightens the web, and 

 draws up a loop of thread between her front 

 and hind feet, Fig. 39, lower figure. 



