:y26 Journal of the Department of Agriculture. 



This tick is common and widely distributed in Soutli Africa. It 

 is parasitic upon* cattle, liorse, mule, sheep, g'oat, dog", hares, and 

 diii'erent species of buck. It is found on the head or l»ody, or in the 

 cars of its host. 



Life History. — The JJrown Tick requires three hosts in order to 

 complete its life cycle. The females lay about 3000 to 5700 eggs, 

 which take about twenty-eight days to hatch in summer, and from two 

 to three mouths or more in winter. The larvae remain on their host 

 from three to seven days, and after dropping off moult into- nymphs in 

 sixteen to twenty-one days. The nymphs also remain three to seven 

 days on their host. They moult into adults on the ground after a 

 period of about \e\\ to eighteen days. The females usually remain 

 on their host for about a week, but in some instances the period may 

 be prolonged to about three weeks. 



Larvae have been kept alive without Icod for seven to eleven 

 months, the nymphs for six and a hair uionths, and the adults for 

 nearly twenty-six months. 



Relation to Disease. — The Brown Tick is the chief transmitting 

 agent of East Coast fever to cattle, and has also been proved to be 

 capable of transmitting the disea.se foimally known as " gall-sickness " 

 in cattle, whicdi is produced by Piroplasiini mutatis, red^vater in cattle 

 and gastro-enteritis, or " Nairobi Sheep Disease," as it is commonly 

 called, which occurs in sheep and goats in British East Africa. 



East Coast fever may be transmitted either by the nymphs which 

 become infected through feeding on an animal suffering from the 

 disease in their laiwal stage, or by the adults which got infected in 

 their nymphal stage. Infective nymphs and adults lose their infec- 

 tion after feeding on a clean animal. Eedwater may be transmitted 

 either by adults which have fed on an infected animal in their 

 nymphal stage or by larvae whose mothers acquired the infection 

 through feeding on an infected animal. There can be little doubt, 

 however, that the Blue Tick is the chief earner of the organism pro- 

 ducing this disease in this country. " Nairobi Sheep Disease " was 

 demonstrated by Mr. Montgomery in East Africa to be transmitted by 

 the adults, which became infected throng^ feeding on an infected 

 animal in their nymplial stag'o. Fortunately, this disease does not 

 occur in the ITnion. 



The Cape Brown Tide (Ivhipicephalus capeusis, Koch). 



This tick is by no means common in South Africa. It closely 

 resembles the common Brown Tick, from which it is mainly distin- 

 guishable by the scutum or shield l)eing more densely covered with 

 small pits or punctations. It has also been proved to be capable of 

 transmitting East Coast fever to cattle. Other hosts of this tick are 

 the horse, goat, and dog. 



The life cycle is 'similar to that of the foregoing species. 



The Blach-pitted Tick (Rhipicephalus simus. Koch). 



This tick can be distinguished from the other brown ticks .by the 

 ^:cutum being darker in colour, and by the punctations on its surface 

 being fewer, and in the males they are usually arranged in longi- 

 tudinal lines. The males when fed sometimes possess a tail. It is a 

 fairly common species in South Africa, and is usually found attached 



