216 AMERICAN SPIDERS 



as winter quarters. Much more durably constructed than the diving 

 bell, this home is usually a closed sac spun in the cavity of an empty 

 snail shell or a similar shelter. During the cold months the spider 

 lies dormant, its life processes at such low ebb that the small cham- 

 ber of air proves adequate to its oxygen needs until the advent of 

 warmer weather. 



THE FUNNEL- WEB SPIDERS 



The most generalized members of the whole series of three- 

 clawed hunting spiders are the numerous diverse representatives of 

 the family Agelenidae: the funnel- web spiders. In physical appear- 

 ance they are far less changed from the hypothetical prototype of 

 the group than are the wolves and fishers and lynxes. Unlike these 

 latter, which are extroverts and big-eyed hunters, most of the agele- 

 nids are quite shy and hide under debris or in vegetation in their 

 funnel webs. While they are still good hunters for the most part, 

 with strong bodies and powerful chelicerae, this activity has become 

 contained within the limits of the silken field that they lay out over 

 the terrain. Since they spin a web and do use it to trap insects, they 

 are called sedentary spiders, but they represent a quite separate 

 line from the aerial sedentary spiders. 



The cephalothorax of the agelenids is nearly always oval and 

 convex, and the eyes typically lie in two rows near the front edge 

 of the carapace. The eyes are not notable for size in any of the 

 groups; they are far inferior to those of relatives that have to place 

 considerable reliance on sight when hunting. The oval abdomen 

 exhibits as a prominent feature spinnerets that, except in less typical 

 members, are quite long, and often have the terminal segment of 

 the hind pair conspicuously lengthened. The whole body is covered 

 evenly with plumose hairs. The legs are long and thin, particularly 

 in the most active forms, and are never supplied with brushes of 

 hairs beneath the apical segments. In commenting upon the physical 

 characteristics of the agelenids, it can be said that evolution has 

 caused them to modify their bodies, especially their eyes and legs, 

 far less than their vagrant cousins have done. Thus they are called 

 generalized; but at the same time, in regard to their way of life, 

 they have become highly specialized. 



The funnel web of the agelenids is little changed from the silken 

 cell of their forebears, and they still hide it under stones or logs, in 



