xni] SPINNING APPARATUS AND FEET 119 



other point of structure of which the reader has been 

 promised some account. Attention was directed to 

 the fact that while some spiders are helpless on 

 smooth perpendicular surfaces unless they have lines 

 to cling to, others can run with ease upon the walls or 

 even the ceiling, of a room. 



The last joint or tarsus of the spider's leg is very 

 different in the two cases. It always terminates in 

 claws either two or three so that any species can 



Fig. 13. Foot of Jumping Spider (on left), foot of Garden 



Spider (on right). 



make some show of climbing where the surface is 

 rough and there is anything to cling to, but to obtain 

 a hold on a polished surface it needs a special con- 

 trivance. This takes the form of a pad of curiously 

 modified hairs, called a scapula. The hairs are club- 

 shaped, narrow at their stalk and swelling towards 

 the tip, and their clinging power seems to be due to a 

 viscid secretion. The foot of any jumping spider will 

 show r this structure well. Epeira has no scopula, and 

 its climbing is always laborious unless it has a thread 



