THE HUNTING SPIDERS 217 



crevices, and in deep vegetation. The funnel is open both in front 

 and behind, thus providing the spider with a rear exit if it is men- 

 aced. From the outer opening of the retreat is spread an expansive 

 field of white webbing the sheet web which may be placed on 

 or just above the soil, or suspended high in vegetation like a ham- 

 mock. It forms a smooth runway on which flying insects can alight, 

 under the mistaken impression that it is a suitable landing field. 

 Once down, they find it a spongy, yielding trap into which they 

 sink and over which they drag their bodies with difficulty. For 

 the spider, the sheet is a racing course; it is able to run over the 

 surface with great speed in an upright position, and catch its prey 

 before the insect can reach the edge of the snare. 



The typical agelenid sheet web, composed entirely of dry silk, 

 grows up with the spider to adulthood, changing from a small, thin 

 mesh into a thick blanket of considerable expanse. It grows by ac- 

 cretion, the result of incessant spinning by the active spider during 

 most it its life. Upon a framework of long dragline threads, coming 

 from the front spinnerets, and outlining the sheet, are put down 

 many finer lines drawn from the hind spinnerets, which move from 

 side to side like brushes and lay multiple filaments. The sheet web 

 is rarely a simple, two-dimensional structure; suspended above it 

 will be a network of lines, placed in irregular fashion and attached 

 to adjacent grass or twigs, which serves as a barrier to jumping and 

 flying insects and causes them to drop upon the sheet. 



Our best-known agelenids, the grass spiders of the genus Agelena 

 and related genera, scatter their sheets in immense profusion over 

 grass and shrubs, often high above the ground, and frequently on 

 or inside houses. In the autumn these webs reach their greatest 

 size, and, seen in early morning when they are covered with dew, 

 seem to carpet acres of grassland. The spiders themselves are of 

 moderate size, with bodies ranging from one half to more than an 

 inch long, and are colored variously from pale yellow to dark 

 brown. The cephalothorax has light median and lateral stripes, 

 while a broader, speckled band runs the length of the abdomen. 

 Three or four well-marked species, differing in size, color pattern, 

 and habits, will be found in almost any single locality in the United 

 States. 



Agelena sits in the mouth of her funnel retreat, facing the sheet 

 and poised for a swift foray over its surface. A June beetle drones 

 through the air and strikes the aerial network; its flight is abruptly 

 arrested, its heavy body plummets to the surface of the sheet; the 



