1 66 



THE ANIMALS AND MAN 



many silk-glands in the abdomen, from each of which a 

 fine duct runs to a spinning-tube. 



The spiders may be divided into two groups according to 



FIG. 75. The dog- or wood-tick, Dermacentor americanus, male, the most 

 abundant tick in the Northern States. (Natural size indicated by 

 line; after Osborn.) 



their habits, viz., the wandering or hunt- 

 ing spiders, which do not spin webs to 

 catch their prey, and the sedentary or 

 web-weaving spiders, which spin snares to 

 catch their prey. The wandering spiders 

 can spin silk, however, and often do so to 

 line their burrows, to make nests, or 

 to make egg-sacs. The hairy tarantulas 

 and the trap-door spiders of similar appear- 

 ance are among the most interesting of the 

 hunting spiders. They live in vertical 

 burrows or tunnels in the ground which 



FIG. 76. The 

 eyes and 

 mandibles of 

 a spider. 

 (Much e n - 

 larged; after 

 Jenkins and 

 Kellogg.) 



