276 



COLLEGE ZOOLOGY 



Ventral view of 

 female showing 

 fiourglass-shaped 

 mark 



Figure 168. Black widow spiders in their snare. The female may kill and eat the male after 



mating, but this is not always true. 



Sarcoptes (Fig. 167), causes the so-called 7- 

 year itch in man, as well as mange in dogs, 

 cats, and many other kinds of animals. 

 Domestic animals are infested by a num- 



ber of species of mites and ticks. The 

 chicken mite (Fig. 167) is a serious pest of 

 poultry. Scab mites attack horses, dogs, etc. 

 The sheep scab mite may seriously injure 



>. Tli*^'!- ■i'M' V' ii ii" iii i i m»'r i Vit^ 'i ii' * i « f>' a ^' i'^' • — -''--^ 



Figure 169. Tarantula, the largest of the spiders. The tarantula does not spin a web, but 

 stalks its prey like a lion. It is found in our southwestern and western states. Although feared 

 by many people, experiments on species in this country have shown their "bites" to be no 

 more harmful than a bee sting. However, it is true that some South American tarantulas are 

 more injurious. (Courtesy of N.Y. Zoological Society.) 



