THE ARACHNIDS AND THE MYRIAPODS 119 



emerge. By successive molts, without marked metamorphosis, 



they reach their adult size. 



The dark-colored, hairy spiders (Lyco'm) found under 



sticks and stones usually build tubular nests in the ground, 



which they line with silk. They do not 



make a web to capture their prey, but 



spring upon it as they run about in search 



of food. The females may often be seen 



dragging after them the large gray ball 



which contains, at first, their eggs, and 



afterwards the young. After a certain 



time the young leave the silken case, and 



for some time longer run about over the 

 body of the mother. 



These spiders are 

 often called tarantulas, 

 but that name should be 

 restricted to the large, 

 hairy spiders of the 

 warm parts of the world, 

 which can be distinguished from all other 

 spiders by the fact that the terminal seg- 

 ment of the mandibles works vertically 

 instead of horizontally. Tarantulas are 



universally dreaded in the countries where 

 FIG. 01. Trap-Door , , . . 



Spider Burrow, the J g row to be of lar g e Slze > and the J are 

 showing Side Tube, believed to be very poisonous. The ability 

 Reduced. (After of ider to tl human skin 



Emerton) \ 



depends, of course, on its size and the 

 strength of its jaws ; the effect produced by the bite depends 

 not only on the amount of poison injected into the wound 

 but also on the age and mental and physical condition of 

 the person bitten. Though many stories of death by taran- 

 tula bites have been told, most of them are clearly untrue. 



FIG. 60. Egg-Case of 

 the Garden-Spider. 

 Natural size. (After 

 Wilder) 



