THE WAYS OF LIFE 



211 



evidence 

 that the 

 spinner im- 

 proves by- 

 practice. 

 The first 

 web made 

 by the 

 spiderling 

 has all the 

 parts seen 

 in the web made 

 by the adult. 

 Montgomery has 

 shown, in species 

 of Epeira, that 

 as the spiders 

 grow older the 

 thread becomes 

 thicker and the 

 web larger ; there 

 are a few more 

 radial rays and a 

 few more loops 

 in the spiral, but 

 these difEerences 

 are correlated 

 with the in- 

 creased weight 

 of the spider and 

 the increased 

 size of the spin- 



FiG. 39. — ^Young garden 

 spiders, moving 

 around their nest, 

 rising and sinking 

 on threads of silk, 

 and congregating 

 in a central mass. 

 (After Roesel.) 



