98 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



below the shield space upon the web of the spiderling Argiope, in the 

 early part of June, when the little creature evidently had been but a few 

 weeks, probably a few days, out of the cocoon. 



The purpose of this zigzag is an interesting problem ; it evidently has 

 no special purpose in the daily life habits of the spider ; at least, close 

 and continuous observation of many species colonized upon my ])remises 

 have uncovered nothing. I believe that it serves to strengthen the shield 

 in its position at the hub, staying it by the broad bands wdiich bind to- 

 gether and support the radii. The great weight of the sj)ider is thus 



Fig. 90. The central part and upper foundation lines of Argiope's snare. 



distributed over a much larger part of the orb. It probably answers a 

 similar purpose when the spider is engaged in swathing the large insects 

 which often serve it for prey, the strong zigzag cord and central shield 

 forming a secure attachment for the binding cords, thus keeping the net 

 intact against the struggles of the victim. 



This zigzag on the snares of Argiope is the nearest approach in nature 

 to that "winding stair" up which the cunning old spider in the school- 

 book rhymes of "The Si)ider and the Fly" dragged liis "silly" victim 

 "into his dismal den." Argiope certainly does pass over it to the lower 

 part of her snare; but the ordinary open radii on other orbs are also thus 



