THE TKIAXGLE SPIDER : THE OKB SECTOK. 



183 



Making 



the 



Frame. 



Fig. 171. 



Making the frame of the Triangle spider's 

 snare. 



The mode of spimiing the foundation lines or frame has never been 

 observed, as far as I know, by any naturalist. A careful study of a number 

 of webs, however, has led me to con- 

 clude that it is spun as follows : In 

 the first place, the spider stretches 

 between two points a sin- 

 gle line, which we may rep- 

 resent by the dotted line, 

 PB, in Fig. 171. She then 

 proceeds to attach to this line, say at 

 the point A, another thread, which 

 is carried along the original line, 

 PB, to the place of attachment, B. 

 Thence up the branch or other object to C, where the carried line is 

 drawn taut and fastened. There is thus produced the line AC, and the 



original foundation line having been drawn 

 upward by pulling upon AC, has assumed 

 the curved form of AB. The two outer 

 radii of the snare are thus in place. Now 

 the spider drops from the point CB, carry- 

 ing with her a thread, which is attached at 

 B, and becomes thus the base line of the 

 triangle CABC. Proceeding along the line 

 BA, carrying with her a thread as before, 

 she makes another attachment at E, returns 

 upon her course to B, and thence upward 

 to E, on the base line where the carried thread is straightened, fastened, 

 and the third radius, EE, completed. In a similar way the fourth radius, 

 DD, is stretched. This, of course, 

 does not express the exact order in 

 every case, but the general method. 

 It will be observed that these 

 radial lines do not meet in a com- 

 mon point. This is in- 

 deed contrary to most 

 published descriptions of 

 the appearance of the 

 snare. For example, 

 Thorell speaks of these threads in 

 the net of Ilyptiotes paradoxus as 



Fig. 172. Frame or radial lines of Hyptiotes' 

 snare, as in nature. 



IN 



1st 



Have 

 Radii a 

 Comnion 

 Point ? 



Fig. 173. 



Natural arrangement of radii, to show the order 

 in which they are spun. 



forming " equal angles with the original thread, and each other." ^ Em- 

 erton speaks of the apex as " the point where the rays meet." - He again 



^ European Spiders, page 70. 



New England Spiders, Family Ciniflonidie. 



