194 AMERICAN SPIDERS 



Few of the hunters have completely given up the silken cell as 

 a base. Some found such comfort there that they have remained in 

 it throughout their history, and have modified it only by embellish- 

 ing the entrance with various types of webs. Ariadna lies in the 

 tube and waits for insects to trip on the signal lines that radiate 

 from the mouth. Many funnel-web spiders spin a little silken collar 

 around the opening and await callers with like patience. The well- 

 hidden funnel of the grass spiders provides a sanctuary from the 

 gate of which the spider may survey its vast sheet web where drop 

 leaping or flying insects. All these spiders are fundamentally hunt- 

 ing types; they represent a very distinct line from those creatures 

 that use the third claw as a hook to swing through space. The 

 sedentary vagrants rarely produce aerial webs of consequence, and 

 they emulate only poorly the superb devices of the aerial snarers. 



Most of the early hunting spiders found it advantageous to move 

 away from the bonds of silk. Improvement in vision made possible 

 a life of action far from the retreat even during the daytime, and 

 some were quickly molded into swift vagrants, with little need for 

 a fixed station. Two distinct lines have been followed by the 

 higher hunting spiders: one culminates in the wolf and lynx spiders, 

 and the other in the jumping spiders. 



Whereas the curved, unpaired claws were the prime determi- 

 nants of the departure of the aerial spiders from the main line of 

 spider evolution, these had little to do in laying down the path of the 

 vagrants. The wolf spiders and their kin retain the median claw, 

 but it is small in size and not used as a hook. No claw tufts or 

 accessory claws are ever present, but in some of the heavy ground 

 forms the lower surface and sides of the distal leg segments are 

 covered with thick pads of hairs. The gradual development of 

 better eyesight in their prototypes made possible longer and longer 

 forays away from the cell, thus leaving the egg sac vulnerable to the 

 attacks of predators. During the egg-laying season the females 

 remained near their sacs to guard them from depredation, and fre- 

 quently were on hand until the progeny had emerged and dispersed. 

 The lynx spiders and funnel-web spiders still guard their eggs in 

 this fashion. Other early spiders learned to mold the flattened egg 

 sac into a round ball and carry it around with them by the mouth 

 parts beneath the body. The fisher spiders still use this cumber- 

 some method. Both the stationary vigil and the unwieldy ball put 

 strong restraint on the normally active lives of these spiders. To 

 ease the curb, some transferred the round sac to their spinnerets so 



