36 VETERINARY PARASITOLOGY 
that the parasite first becomes a carrier of the various 
piroplasms, which cause those diseases grouped under 
the heading of ‘“‘ piroplasmoses,” and it is as an 
adult that it transmits the piroplasms to another 
animal. 
Except in the role of a transmitter of disease, none of 
the ticks harm their host to any extent. At the most, 
and only then when in considerable numbers, they give 
rise to itching, and possibly anemia. We append a list of 
a few of the diseases due to piroplasms, together with 
the ticks which transmit each : 
British Redwater.. .. Ixodes reduvius | Probably 
Ixodes ricinus identical. 
Hemaphysalis punctata. 
(In the pig) Ixodes plumbus. 
Texas Fever .. Rhipicephalus annulatus or bovis. 
South African Redwater Rhipicephalus Australis, var. de- 
coloratus (blue tick). 
Rhodesian Redwatey .. Rhipicephalus appendiculatus 
(brown tick). 
“ Carceag’’ of Sheep .. MRhipicephalus bursa. 
Malignant Jaundice, ov Hemaphysalis Lechi. 
Canine Pivoplasmosis 
South African Heartwater (In sheep) Amblyomma Hebreum. 
It is difficult to eradicate ticks from a farm, but the 
following methods are adopted : 
1. Ploughing all rough pasture, trimming hedge- 
bottoms, and dressing the land with salt or lime. 
2. Removal of ticks from infested animals by hand 
and by dipping. 
3. Pasturing animals of a different species on the 
land, in order that the piroplasms may gradually die 
out. The ticks, however, are not easily destroyed by 
this means. 
The other non-psoric Acari are of little importance. 
The autumn grass mite Leptus autumnalis) is the 
hexapod larva of the harvest mite (Trombidium holo- 
