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may serve as a host. If need be, they remain thus on the 

 alert for several months, patiently Baiting through wind, 

 sun, and rain. If the larva succeeds in attaching itself to 

 a cow or some other animal, it feeds, and then moults to 

 become an eight-legged nymph. The nymph takes another 

 meal and sheds its skin to emerge as an adult tick. There 

 are a number of species of ticks in the United States. 

 They attack man, poultry, and other animals. 



Though ticks may cause some trouble and inconvenience 

 by sucking blood, their chief claim to economic importance 

 lies in their ability to transmit diseases. The cattle tick 

 carries Texas fever. This disease is caused by a proto- 

 zoan parasite, Babesia bigemina, which not only flourishes 

 inside a tick in the blood sucked from an infected animal, 

 but may also be transmitted by a female tick to her off- 

 spring. The national government has recently worked 

 out methods for the eradication of Texas fever. One of 

 the best is the rotation of cattle through several pastures 

 so as to free them from ticks. The disease has caused losses 

 amounting to $100,000,000 in a single year in the United 

 States. Another tick, Dermacentor andersoni, is prevalent 

 in certain parts of the northwestern United States. It 

 carries and transmits the spotted fever, or mountain fever, 

 a fatal disease. In West Africa ticks are very numer- 

 ous and carry most of the prevalent fevers affecting man 

 and other animals. Several cases have been recorded in 

 America in which paralysis occurred in persons bitten by 

 ticks. 



