THE SPIDER AND ITS ALLIES 



81 



contrast to the condition in other orb-spinners, in which 

 a sector of the circle is omitted or in which a sector only 

 is formed. At the centre of the web of Argiope there is 

 an oval, closely woven shield of silk. The spider, when at 

 rest, is usually found upon or under this shield. Another 

 frequent character of the web is a zigzag ribbon,, extending 



FIG. 78. Web of Argiope, placed horizontally over a fish-way. Photo, 

 by W. H. C. P. 



downward from the central shield, and sometimes upward 

 also, and attached to two or more radii. This zigzag, 

 which is doubtless the " winding stair " referred to in 

 the rhyme, " The Spider and the Fly," is formed, as Fig. 

 79 shows, by preventing the fusion of the strands as they 

 emerge from the spinnerets. 



