Superfamily Argiopoldea 



which extends through the hole in the board upon which it is 

 built; but is considerably smaller than this hole, so that it can 

 easily vibrate in it (Fig. 284). On the inner surface of the board 

 the net-work is continued as a sheet resembling somewhat that on 

 the outer surface. It is probably upon this sheet that the spider 

 waits for its prey. Here it is concealed from sight but is in a 

 position to detect any vibration of the web. 



But the most characteristic feature of the web is a series of 

 radiating lines, which consist of a doubled plain thread supporting 

 a looped hackled band. In making these lines the spider spins 

 a thread of plain silk, which consists of several parallel strands, 



BjjctaMg s 



fc. 



Fig. 285. HACKLED BAND OF FILISTATA 



from near the centre of the web to a distant point, where it is 

 fastened by an attachment disk; the spider then returns to the 

 starting point spinning as it goes another similar thread closely 

 parallel to the first. Upon these two threads, which serve as a 

 foundation, are fastened afterward loops of a hackled band. 

 This doubled supporting line and the loops of the hackled band 

 can be seen with the unaided eye, and are shown in Fig. 283. 

 A small section of one of the radiating lines is shown greatly 

 enlarged in Fig. 285. This picture is from a photomicrograph 

 and is not as perfect as could be desired; for with the high magnifi- 

 cation necessary to see the details it was impossible to get all 

 parts of a loop in focus at once; hence each loop appears blurred 

 in a part of its course. 



Four kinds of silk enter into the formation of this remarkable 

 structure. First,- — the doubled supporting line; this appears 



296 



