THE CRIBELLATE SPIDERS 149 



because of the paralyzing effect of the poison injected at the 

 bite; but to make certain that it cannot escape, the moth is en- 

 shrouded in silk spun across it, the hind legs drawing out the silk 

 from the spinners and applying it to the insect. 



This method of snaring a victim was compared by Ackerman to 



enveloping it as the Retiarius with his net enveloped his oppo- 

 nent before piercing with his trident in the Roman gladiatorial 

 combats, or better, like the old-fashioned butterfly net on two 

 sticks, held by the two hands, which was thrown over an insect 

 to catch it. 23 



A single web suffices Menneus for a whole night of casting. 

 After removing a victim from the sticky lines, she pulls and read- 

 justs until the web again takes its essential rectangular shape. Then 

 she resumes her vigil, feeding on the unlucky insect while she holds 

 what may be only a tattered remnant of her snare. When the spider 

 has satisfied her appetite, and usually with the approach of morn- 

 ing, she rolls up the web and some of the adjacent foundation lines, 

 drops the ball to the ground, and moves to her normal daytime 

 resting place against a twig. 



This intriguing method of capturing prey has no exact counter- 

 part among spiders of any other family, but the device parallels in 

 a general way that of the bolas spider (vide infra). 



Hackled-Eand Orb Weavers. An outstanding achievement of 

 the Uloboridae has been the invention of an aerial orb web equal 

 in symmetrical beauty and similar in fabrication to that of the 

 ecribellate orb weavers. It is believed by many that this creation is 

 a novelty separately arrived at, not one result of an ancient habit 

 common to allied spiders that later diverged. The germ of an orb 

 web is observable in the great regularity of the webs of hackled- 

 band spinners less versatile than the Uloboridae. Even the irregular 

 mats of Amaurobius and Filistata are based on a framework of dry 

 rays arising from a central retreat. Many species of Dictyna spin 

 aerial sheets of such regularity that in form they approach sectors 

 from the webs of the uloborids. 



Once a symmetrical design had been realized, lifting the orb 



23 C. Ackerman, "On the Spider, Menneus camelus Pocock, Which Con- 

 structs a Moth-catching, Expanding Snare," Annals of the Natal Museum, 

 1926, p. 418. 



