42 



Guide to Insects and Ticks 



Ornitliodoros savignyi is very widely distributed in Africa, from 

 Egypt to Cape Colony, and is also recorded from Southern India. 

 It occurs on both man and domestic animals, and experiments 

 have shown that the species is capable of transmitting the human 

 relapsing fever of tropical Africa. 



Dcrmaccntor venusius is a North American form, ranging from 

 British Columbia southwards to Northern New Mexico, and from 

 the foothills of the Eocky Mountains in Colorado to the base of the 

 Cascade Eange, in Oregon and California (see map). Almost all 

 the small mammals found in the localities in which this tick occurs 

 serve as hosts for the larvae and nymphs. The adult tick is 



f\ if'* 



Fig. 14. — Ax Afeicas Tick, 



Omithodofos moubata, female, under surface, X 4 : larjrely lespousilile for the spread of 



the relapsing fever of Africa. 



nearly always met with on the larger domestic animals, especially 

 on horses and oxen. The species also attacks man, and transmits 

 the spotted fever of the Eocky Mountains, a disease with a high 

 rate of mortality. According to some authorities, more than 

 one species has been included under the name D. venustiis, and 

 the species conveying Eocky Mountain fever should be called 

 D. andcrsoni Stiles. 



The second group exhibited comprises examples of ticks that 

 convey disease to domestic animals, but not to human beings ; it 

 includes the following species : — 



lihipicephalus cvcrtsi Nn. is a tick found in most parts of 

 Africa (see map), and transmits East Coast fever of cattle and the 



