GENERAL CHAKACTERISTICS OF OKBWEAVEKS SNAKES. 



Certain species (indeed, the habit has its representatives among several 

 genera) further strengthen the notched space by a close, plain band of 

 white silk, which ordinarily extends between two radii, along the perpen- 

 dicular diameter ui)ward from the hub to the spiral space. (Fig. 54.) 

 Sometimes al.so the ribbon reaches both upward and downward from the 

 hub, and takes tlie form of a scalloped band or thick winding cord. This 

 peculiarity prevails in all our indigenous examples of the genus Acrosoma, 

 and is also quite characteristic of the exotic species of the same genus. 

 Our beautiful and familiar representatives of the genus Argiope (A. cophi- 

 naria and A. argyraspis Walck.)i have the same habit. (See Figs. 55.) 



Some species, as frequently Argiope argyraspis, add to this perpendicular 

 ribbon, on either side thereof, one or more semicircular zigzag cords, which 

 further tend to strengthen the central jiart of the orb. Some species of 

 Uloborus have a similar habit, but also at times throw the cord entirely 

 around the notched space, making a series of circles. (Figs. 56 and 57.) The 

 perpendicular cords are sometimes extended above and below the notched 

 space, and terminate in serpentine folds, bulb shaped tufts, or tapering 

 points. They give a striking and beautiful appearance to the web, the 

 graceful lines, and thick, white, flossy texture showing in j)retty contrast 

 against the radii and spirals. Examples of these peculiarities will be found 

 among the descriptions of characteristic webs. (See Chap. VI.) 



These bands and cords, besides probably serving as braces, are used by 

 the spider as sujiports when she hangs at the oj^en hub. Acrosoma rugosa 

 will generally be found hanging by her hind pair of legs to the lower end 

 of the ribbon. 



' E|ieira fafciuta Hcntz, ami AririnpL' transversa Eniertoii. 



