i 5 4 AMERICAN SPIDERS 



tance from the first. The final number of these partial spirals varies 

 from ten to more than twenty. As the series meets the scaffolding, 

 these latter threads are cut out of the web. 



The finished web is an extraordinary structure, and is employed 

 in an extraordinary way to provide the spider's food. Hyptiotes 

 takes up a position at the end of the bridge line, near the apex of the 

 triangle, her hind legs touching the silken anchor almost in contact 

 with the twig. With her front legs she pulls the line until the whole 

 web becomes taut; then, holding the slack thus gained over her 

 body, she settles down to wait for her prey. A small moth or other 

 flying insect strikes the web and adheres, struggling violently in the 

 viscid coils. Immediately Hyptiotes lets go of the slack. The web 

 snaps forward, carrying the spider out a short distance with it, and 

 the resultant vibration of the swaying, sticky line causes the victim 

 to become more firmly enmeshed. Hyptiotes seems able to estimate 

 the character of the insect from the nature of its frantic struggles 

 and acts accordingly. The snare may be drawn tight once more 

 and snapped, and this action will be repeated again and again until 

 the spider is ready to crawl over her lines to the victim. 



Hyptiotes never bites her prey as do many other web spiders, a 

 fact undoubtedly related to the absence of poison glands in this 

 family. Instead, she comes up to the insect, turns her back to it, 

 and, rolling it over and over with her legs, covers it with a thick 

 bluish web. Completely helpless, the victim is carried back to the 

 resting site and sucked dry in the leisurely manner characteristic 

 of the triangle spider. This method of overpowering prey by means 

 of thick bands of silk is analogous to the habits of the comb-footed 

 spiders and the typical orb weavers. 



Not infrequently, when the trap has been sprung for the first 

 time, Hyptiotes will move forward and, grasping the radii in her 

 front legs and cutting some of the lines, will gradually bundle up 

 the web and hurl sections of it over the victim. By so doing, she 

 destroys the web almost completely, and must spin a new one for 

 her next period of trapping. But inasmuch as one victim provides 

 this small spider with sufficient supply of food for a day or more, 

 the loss of the snare does not materially handicap her. 



One wonders whether Hyptiotes has not gone to more trouble 

 than the web is worth in producing her triangle trap. Although it 

 will probably catch more insects because of its vertical position 

 and greater size, almost as much spinning and silk goes into its fabri- 

 cation as is expended in the horizontal web of Uloborus. Further- 



