i86 



THE COMMON SPIDERS 



The webs of Zilla (fig. 432) have a segment left without cross 

 threads, sometimes for its whole length, and sometimes only 

 the part of it nearest the center. Opposite this open segment 

 a thread leads from the center of the web to the nest (fig. 433), 



which is a tube of silk open at both 

 ends. 



The differences between the palpi 

 of the males are very plain. In atrica 

 the palpi (fig. 434) are as long as the 

 whole body, with the femur and tibia 

 both slightly curved and the tarsus 

 and palpal organ small and like that 

 of x-notata. In x-notata (fig. 435) the 

 palpus is as long as the cephalothorax, 

 and the tarsus and palpal organ small 

 and round. The front legs are a 

 fourth longer than in atrica. In 

 tnontana (fig. 435^) the palpus is still 

 shorter, the tibia thicker, and the tar- 

 sus and palpal organ larger. There 

 is little difference in the shape of the 

 epigynum of the different species, but 

 that of montana is twice as large as 

 that of x-notata or atrica. 



Singa pratensis. — The Sin gas are 

 small Epeiridse a sixth or fifth of an 

 inch long, with smooth bodies and 

 bright colors. They live among grass and other small plants in 

 low open ground. When full grown the females of S. pratensis 

 are a fifth of an inch long, with the abdomen oval and marked 

 with a double white stripe in the middle and a single one on 

 each side. The cephalothorax is yellow, with a little black 

 between the middle eyes not extending to the lateral pairs. 



Fig. 433. Tubular nest of 

 Zilla atrica. 



