;>2() Journal of the Department of Agriculture. 



figures 1, 2, o. and 4), and in any case are not likely to be confused 

 with them, as the latter are mainly parnsitic upon man and animals. 

 ;ind very rarely attack 1)irds. 



This species is the chief transmitting agent of the fowl spirochaete 

 (Spirochaeta mnrchouxi), which is usually fatal to birds. The ticks 

 become infected by feeding upon infected fowls, and are then capable 

 of transmitting the disease to susceptible birds for six or more months. 



Apart from the fact that the ticks are able to transmit a disease 

 to fowls, they do a considerable amount of harm to them, and if they 

 aTe at all numerous they kill their hosts, the birds dying from loss of 

 blood and from the irritating effects produced by the ticks. 



The Life Cycle is as follows: — The female ticks usually lay their 

 eggs in batches of about 20 to 100 in the cracks and crevices of walls 

 of fowl-houses, etc., or under the bark of trees. The eggs hatch in 

 about three weeks, and give rise to six-legged larvae which crawl 

 about in search of a host. They remain attached to the skin of thei]' 

 host for five to ten days, according to the temperature, and then they 

 drop off and moult into nymphae. The nymphae and adults, unlike 

 the larvae, are only temporary parasites, attacking their hosts chiefly 

 at night and hiding during the day in crevices of buildings or under 

 the bark of trees. They are rapid feeders, taking lA to 2 hours to 

 engorge themselves. The first nymph al stage lasts about three weeks, 

 and then they moult into the second uymphal stage, and again, after 

 some weeks, into adults. The adult females feed more plentifully 

 than the males, and usually about once a inontJi during the summer. 

 After each meal they lay a batcli of eggs. Lounsbury found that 

 the complete life cycle from ^g^ to egg* stage occupied about ten 

 months in this country. The larvae are only able to live for about 

 seven or eight weeks without food, but nymphae have been known 

 to live for a year without having had a meal, and the adults for two 

 to three years. 



(2) The Tam-pan (Ornithodoros moubata, Murray). 



This tick is not nearly so widelj* distributed in South Africa as 

 the Fowl Tick, but is usually plentiful in localities where it is found. 

 It usually occurs in desert tracts in the shade of trees and rocks, and 

 in native huts. It is mainly parasitic upon man and his domestic 

 animals. 



This species transmits African Relapsing Fever or Tick Fever 

 to man in Central and East Africa, the Congo Free State, and Angola, 

 and has also been proved experimentally to be able to transmit 

 Spirochaeta inarchouxi to fowls. 



The lAfe Cycle is as follows: — The females lay their eggs in 

 batches in sand or hollows in the ground excavated by the females. 

 The total number of eggs laid by a single female varies from about 

 90 to 150. The larva develops inside the &g^, and the young nympha 

 hatches out in eight to twenty-three days. • The first stage nympha is 

 able to feed soon after hatching, and after gorging moults into a 

 second stage nympha. There may be three or four nymphal stages 

 in all before the ticks reach maturity. Like the fowl ticks they are 

 able to survive for many months without food. 



(3) The Spinose Ear Tick (Ornithodoros Megnini, Dvges). 

 This tick is a native of America, and was probably introduced 

 into the Union with stock coming from that eountrv. 



