Superfamily Argiopoidea 



A long, slender tube is built in the hole that serves as a 

 retreat for the spider. This tube is suspended from a framework 

 of threads, built at the entrance of the retreat, in such a way that 

 any disturbance of the exposed parts of the nest is communicated 

 to the occupant of the tube. 



A fine sheet of silk is made surrounding the entrance of the 

 tube like a collar (Fig. 289). The tubular part of the nest does 

 not show in the figure on account of the darkness of the retreat. 



The most striking feature of the nest, however, is a series 

 of radiating lines, which begin in the framework supporting the 

 outer end of the tube, and extend out a considerable distance 



Fig. 28g. NEST OF ARIADNA BICOLOR 



from the nest. Each of these lines passes over two or more piers, 

 which keep it suspended a short distance from the face of the block. 

 There is a set of piers on the edge of the hole in which the tube is 

 built, these are not well-shown in the figure but are very conspicu- 

 ous in the specimens; and there is another set a considerable dis- 

 tance beyond the outer edge of the collar of the tube. 



The radiating lines being held some distance from the face 

 of the block by the supporting piers, are in position to be dis- 

 turbed by any passing insect. And this disturbance is commu- 

 nicated to the framework supporting the tube. The spider waits 

 within the tube with six of its eight legs projecting forward ready 

 to make a leap. The touching of one of the trap lines by an insect 

 results like the touching of the spring of a jack-in-the-box. The 



