THE TRIANGLE SPIDER : THE ORB SECTOR. 



185 



three hundred times in a minute, and in so doing they draw out a 

 double Hne. 



" The spider moves slowly along the radius until she reaches a point (5) 

 where she can step across to the next radius. While so doing, she ceases 

 to draw out the double line, and carefully keeps it from contact with 

 either of the radii. She then reverses her course and moves along the 

 second radius to a point (G) nearly under that whence she started. The 

 double line has shortened itself considerably ; any slack she draws in, and 

 then turning about, with her head toward the apex, she makes a second 

 attachment with her spinnerets close pressed against the radius. This 

 done, she again hangs from the radius, draws out the spiral line, and ad- 

 vances toward the apex, crosses at 7 to the third radius, returns thereon to 

 8, and makes a third attachment. She then repeats the same 

 process upon the third radius, and in Fig. 7 is repre- 



sented (at 9) as %kB having fini-shed about one-half of the line." 



The number 

 of crossed lines 

 when the work 

 is completed va- 

 ries, according 

 to Wilder, from 

 six to sixteen. 

 The European 

 Paradoxus, ac- 

 cording to Thorell, spins from sixteen to twenty-two. 

 According to my own count the number is not constant, 

 but the prevailing number is nearlj' sixteen. I have counteTi 

 five, fourteen, nineteen, and twentj'-two on snares in the same 

 general site. The number is not constant even with the same 

 individual. A female that spun fourteen spirals on one day had nineteen 

 the next ; and like differences showed in the other parts of the snare. 

 Evidently there is no mechanical necessity in the constitution of the ara- 

 nead that compels it to a machine regularity of product. 



These lines are not single threads, covered with viscid beads, as in the 

 case of most Orbweavers, but resemble those of Uloborus, as heretofore 

 described. That is to say,- as they exude from the spinnerets and cri- 

 bellum, they are teased, or to borrow a word from the flax manufac- 

 turer, " hackled," by the calamistrum into a somewhat irregularly widened 

 flocculent mass. 



Wilder speaks of the spiral thread as simply double lines, the two 

 strands being from one five-hundredth to one two-thousandth of an inch 

 apart. ^ Emertou says that it "has a strong smooth thread through the 



Fig. 174. Mode of spinning floc- 

 culent spirals of Hj-ptiotes. The 

 Spider's progress from 4 is shown by 

 the course of the arrows. (After Wilder.) 



^ Op. cit., page 649, note. 



