32 MEDICAL ENTOMOLOGY 



of the same to fix the general characteristics of each in your 

 mind. 



A. Ixodinae. 



a. Amblyomma americanum is the Lone Star tick. Notice 

 the bright silvery spot at the posterior end of the scutum. 



b. Dermacentor venustus is the Rocky Mountain spotted 

 fever tick. Notice the large size of the scutum, which has a 

 dark lyre-shaped figure upon it on a silvery background. 



c. Rhipicephalus sanguineus is the brown dog tick. 



d. Ixodes scapularis is the black legged tick or American 

 castor bean tick; the scutum is chestnut colored as in the Texas 

 fever tick, but the body has the shape of a castor bean, the legs 

 are black, and emerge from the body quite close to the mouth- 

 parts. 



e. Rhipicephalus appendiculatus is one of the ticks respon- 

 sible for the transmission of African coast fever of cattle. 



B. Argasinae. 



a. Ornithodorus moubata is responsible for the transmission 

 of African relapsing fever of man. 



b. Argas persicus is the Persian poultry tick, to which Argas 

 miniatus is very closely related. These ticks are responsible for 

 the transmission of Fowl Spirochaetosis. 



EXERCISE 18b 



LIFE HISTORY STUDY OF THE TICKS 



A. Examine a prepared slide of tick eggs. 



B. If available, examine an ovulating female tick. Notice 

 that the mass of eggs lies anterior to the body, with the head 

 buried in it. Why? 



C. Examine mounted specimens of ticks that have recently 

 emerged from eggs, noting particularly the number of legs. ; 



