?>M Journal of the Department op Agriculture. 



J'/ic Bont Ttck (xViul)lyomj)i;i lu'l)i;t(MU)i, Koch). 



Characters. — All the species of Aviblyomma are as a rule easy \o 

 identify owing to cliaracteristic coloured markings on the scutum, 

 wiiicli differ in the different species. The following characters are 

 common to all species belonging* to the genus Amhlyomma: — 



Scutum generally ornamented and the legs banded : rostrum and 

 ])alpi long; eyes and festoons present; males without adanal shields. 



The males and females of the Bont Tick have the scutum 

 yellowish with usually a red and green tinge, and with dark brown or 

 l)lack markings. 



This tick is widely distributed in South Africa, but more 

 Frequently occurs on the low than on the high veld. It is parasitic 

 upon all the domestic animals and upon a number of wild animals, 

 also on fowls and ostriches. They usually attach themselves to the 

 scutum and anus of their host, but also occur on the body. 



Life History. — It is a three-host tick. The females may lay as 

 many as 18,500 eggs, which takes about 7 to 10 weeks or longer to haiidi . 

 The larvae remain on their host from 4 to 20 days, and moult into 

 nymphs in from twelve to four months after dropping off. The 

 nymphs take from four to twenty days to engorge, and after dropping 

 off usually remain on the ground 18-25 days before moulting into 

 adiilts, but have been known to take 160 days to moult. The females 

 take 6-25 days to engorge, and after leaving their host, remain on 

 the ground from a week to ten weeks before they commence egg-laying. 

 Larvae have been kept alive without food for almost a year, the 

 nymphs for 180 to 250 days, and adults for nearly two years. 



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

 agent of heartwater to cattle, sheep and goats in South Africa. The 

 disease is transmitted by either the nymphs which have fed on an 

 animal suffering from the disease in their larval stage, or by the 

 adults, which fed in their larval or nymphal stage on such an aimal. 



jS'ymphs which acquired their infection in the larval stage can 

 feed on a non-infected animal without losing the infection. 



The Variegated Tick (Amblyomma variegatum, Fahr.). 



Characters. — This tick can be recognized by the scutum of the 

 females and males being redtfish-yellow bordered with green, and with 

 black markings. 



This species is found in parts of the Transvaal and Cape Pjo- 

 vince, but is by no means a common species. It is principally found 

 on cattle, but also occurs on horses, goats, sheep, zebra and rhinoceros. 



The life cycle is similar to that of the Bont Tick. 



Relation to Disease. — We have recently proved by experiments 

 that the Variegated Tick can transmit heartwater to goats. A number 

 of nymphs, which had become infected in their larval stage through 

 feeding on an animal suffering from the disease, were sent to us from 

 East Africa by Mr. Montgomery. On arrival the majority were 

 found to be dead, but 30 were placed in the ears of three goats, five 

 in each ear, and two of the goats showed typical symptoms of the 

 disease and died. Blood taken from tbese goats and injected into 

 sheep produced the disease. 



