ARGIOPE AXD HER RIBBONED ORB. 



97 



Central 

 Shield 

 and Band. 



diademata. Her orbs are frequently very large, but in this are wholly regu- 

 lated by site. A good figure of one of these orbs with details accurately 

 drawn is given at Fig. 47. 



The peculiarity which first strikes the observer is the oval shield 

 of white silk tissue which quite covers the hub. This is thickest and 

 closest in the centre, and grows thinner and more open towards 

 the margin, where it gradually merges into the radii which 

 are attached to 

 it. In the adult 

 spider it is usually about 

 two inches long by one and 

 a half wide. 1 Attached to 

 the shield above and be- 

 low, and extending upward 

 and downward between two 

 radii, is a zigzag ribbon of 

 white silk, an inch or more 

 long and one-fourth of an 

 inch or more wide. It 

 traverses the whole central 

 space and extends down- 

 ward about two inches un- 

 til it is lost in the spirals 

 of the lower half of the orb. 

 These upper and lower 

 ribbons vary in their de- 

 gree of regular- 



erally stretched 



between two ra- 

 dii to which they are at- 

 tached on either side ; but 

 sometimes they overspread 

 three radii wholly or in 

 part. Sometimes they are 

 simply irregular patches or 



of the 

 Zig-zag. 



FIG. 89. The orb of Argiope. The spider is represented at the 

 right of the cut, the male near her. 



strips and often are wanting above the shield ; but the lower ribbon is 

 rarely wanting. This variety in the character of the shield appears to 

 be influenced more or less by age. The shield is generally less prom- 

 inent in the young than in the adult spider; nevertheless, it appears 

 often on the orbs of the very young. This is also the case with the 

 zigzag ribbon, and I have seen a perfectly marked zigzag both above and 



1 The shield represented at Fig. 52 measured two inches long and one and a half wide ; 

 another example was one and three-fourths by one and one-half inches. 



