Injtirious to Man. 39 



not lay eggs until it has fed. The spirochaetes are taken up by 

 the tick whilst sucking blood, and make their way into its 

 ovaries, penetrating into the undeveloped eggs. The nyniphal 

 which develops from these eggs is capable of conveying the 

 disease. The spirochaetes can be transmitted to the third genera- 

 tion of ticks, and they can thus convey the disease, although their 

 immediate parents have fed only on blood free from spirochaetes. 

 An affected tick may harbour the disease for months and still be 

 capable of transmitting it. 



The following precautions are advisable in localities in which this 

 tick occurs. Beds should not be placed on the ground, but should 

 be well raised and not allowed to touch the walls ; hammocks are 

 preferable for sleeping purposes. Native houses or other buildings 

 which have become infested with the tick should be thoroughly 

 disinfected, and huts or other premises of little value destroyed 

 by fire. Old camping sites likely to harbour the tick should be 

 avoided whenever possible. Native quarters should be established 

 at some distance from those of Europeans (at least twenty to 

 thirty yards away), and servants and others coming from them 

 compelled to change their clothes before entering sleeping apart- 

 ments used by white people. The preventive methods given above 

 are principally taken from those recommended by Wellman ; see 

 also Drake-Brockman's advice as to the best method of destroying 

 0. savignyi (see below). 



Omithodoros savignyi, Audouin. 



Omithodoros savignyi is very like 0. moubata in general 

 appearance ; the granules of the integument are rounded as in 

 that species, but there are two well-developed eyes on each side 

 of the body, one being placed opposite the first coxa, the other 

 between the coxae of the second and third legs. Although scarcer 

 than 0. moubata, this tick has a very wide distribution in Africa, 

 occurring also at Aden and in Southern India. Its habits are 

 apparently very similar to those of 0. moubata. Brumpt has 

 succeeded in transmitting tick fever by means of 0. savignyi. 



In the Bulletin of Entomological Research for September, 

 1915, Mr. Drake-Brockman gives an interesting account of the 

 habits of Omithodoros savignyi in Somaliland. He says : " This 

 tick is found in the soil in or around the huts on the outskirts of 

 the coastal towns, showing a predilection for the more squalid 

 and insanitary areas where the indigent Somalis reside. In the 



