:i82 Journal of the Department of Agriculture. 



Relation to Diseases.— Thin tick is tlie well-known transmitting: 

 ai^ent of the organisms producing redwater and gall-sickness in cattle 

 in South Africa, and is also the transmitting agent of spirocliaetosis 

 to cattle, sheep, and horses in this country-. The organism whicli 

 causes redwater is known as Piroplasma bigermnu/n. that 

 causing gall-sickness as Anaplasjna w^rginale, and spirochaetosis is 

 (■aused by Spirochaeta theileri . All these diseases are transmitted to 

 susceptible animals by larvae which have become infected through 

 tlieir mothers feeding either on animals suffering from the disease, or 

 on animals which jiave had the disease and recovered, the animals 

 retaining the infection of any of these diseases for an indefinite period 

 after they have recovered from them. 



There is another species of Blue Tick found in Soutji Africa, 

 namely, the Australian Blue Tick (Boophihis tuistralis. Fuller), whicli 

 closely resembles the South African species in appearance. It is not 

 a common tick in this country, having only been found in the southern 

 parts of the Cape Province. Like its near relation, it can tiansrait 

 redwater or bovine piroplasmosis to cattle, and will probably be 

 found capable of transmitting gall-sickness and spirochaetosis. 



The Bont-leq Tick (Hyalomma aegyptiura, lAnn). 



Characters. — Hypostome and palpi long: eyes present; festoons 

 absent; legs red, with pale bands. The males have white bodies, and 

 tjie scutum is dark brown or black : on the under surface of the body 

 tliere are a pair ot adanal shields and two pairs of chitinized points, 

 the first pair being situated on each sirlo of the adanal shields, and 

 tlie second pair beneath them. 



This species is widely distrilajtcd thioughout Africa, and 

 is also found in Southern Europe and Asia. It is not 

 often met with in South Africa, its place being taken in this country 

 l)y the var. ivipressnm, Neu., which is a common tick here; it may 

 eventually prove to be a distinct species. The variety differs from 

 the type mainly in the scutum or shield being much more densely 

 punctated. It is found on all the domestic animals, and also on 

 various species of buck, hares. bush-])igs, and birds, such as the 

 ostrich, fowls, etc. They usually attach themselves to the anus and 

 scutum of their host, but may also be found on the body. 



The Life History. — The Bont-leg Tick requires either two or three 

 hosts for the completion of its life cycle. The females lay on an 

 average about 10,000 to 15,000 eggs, which take about a month to 

 hatch. The larvae take four to fifteen days to engorge, at the end 

 of which time they either drop off their host to moult, or they remain 

 attached to the animal and moult in situ, in which case they engorge 

 and drop off' in three and a half to six and a half weeks after they get 

 on to their host as larvae. The females remain about a week on their 

 host. 



Unfed larvae have been kept alive for a year; nymphs for three 

 months, and adults for over two years Avithout food. 



Relation to Disease. — This tick is not known to transmit any 

 disease, but Prof. Nuttall suspects that it may convey one of the two 

 organisms which causes biliary fever in horses, the assumption being 

 based upon the fact that the geographical distribution of one of the 

 organisms whi«-^h produces the disease mul this tick coincide with one 

 another. 



