502 



Relapsing Fever 



separated by an interval of about two and a half times the distance between the 

 first and second. 



Length 5-12 mm. Width 4-8.5 mm. The female and male resemble each 

 other except that the latter are smaller. Its genital orifice is markedly smaller. 

 In the female the genital orifice is a broad transverse slit which can be made 

 to gape and is guarded by two flaps like valves; in the male the orifice is oval and 

 the valves are absent. The eggs number 50-100, measure 1.3-1.5 mm. in length 

 and 0.8-1 mm. in breadth. They are oval, smooth and of a dark brown or black 

 color. 



Fig. 201. Ornithodorus moubata. Tick that transmits African relapsing 

 fever: a, Viewed from above; b, viewed from below (Murray from Doflein). 



Fig. 202. Ornithodorus savignyi. An, anus; cam, camerostome; cx.I, coxa 

 I; ex. II, coxa II; cx.III, coxa III; ex. IV, coxa IV; cx.f., coxal fold; e, eye; g.a., 

 genital aperture; g.g., genital groove. 



Habitat. Arabia, Nubia, Egypt, Somaliland, Abyssinia, German East Africa, 

 Cape Colony, Rhodesia, Bechuanaland and Portuguese East Africa. In India it 

 is common in the Madras Presidency, in Gujarat, and in many parts of the 

 Bombay Presidency. In Aden it is widely distributed throughout the Hinter- 

 land, where its principal host is the camel. 



Ornithodorus moubata. Patton and Cragg describe this tick as follows: 

 Body almost as broad anteriorly as posteriorly; covered with non-contiguous 

 mamillEe, but with fewer hairs than savignyi. Basis capituli broader than long 

 and shorter than the palps; hypostome withsix principal rows of teeth. Tarsi of 

 legs I, II and III with three humps as in savignyi; those on the pro-tarsus are 



