Similarly, no points of differentiation may be detected be- 

 tween female specimens from Africa and America. The chief diag- 

 nostic characters proposed for these, arching of the eyes and 

 shape of the distal margin of the third palpal segment, appear 

 similar, as are all other morphological features of specimens 

 from both continents. Minning stated that the scutum of Amer- 

 ican B. annulatus bears hairs and the scutum of *B. congolensis * 

 does not . Several African specimens with scutal "Iiairs and some 

 American B. annulatus without scutal hairs are available, though 

 they may "Have been rubbed off the latter. 



Theiler (194.3B) has already observed that the relation of 

 the position of the eye to scutal margin in Boophilus ticks is 

 subject to variation according to degree of engorgement. As 

 already stated (page 296) no differences between length/width 

 ratio of the female scutum can be determined in field- collected 

 material of each species. 



As stated above, it appears that there are no constant 

 differences between American and African popvilations of B. annu - 

 latus . Likewise, it is impossible to differentiate between Amer- 

 ican and African populations of B. annulatus , and specimens col- 

 lected in North Africa, Southern~Burope , and the Near East, which 

 Minning (loc . cit.) referred to as B. schulzei and as B. calcara - 

 tus subspp. ^ " 



In their classic work on this parasite in America, Hunter 

 and Hooker (1907) open by observing "It is safe to state that 



no nore important problem than the eradication of (B. 



annulatus ) confronts the farmers of any country. Not 



only the cattle raising industry but the whole economic condi- 

 tion of a large section of country is affected". 



The Texas fever tick is now completely eradicated from the 

 United States except for periodic introductions from Mexico, 

 where it still exists. At the turn of the century it ranged 

 throvigh Mexico and the sixteen southern states of the United 

 States from the Atlantic to the Pacific. The history-making 

 discovery by Smith and Kilbourne (1893) that Babesia bigemina 

 is the cause of Texas fever of cattle was followed by their 

 finding that this tick is the vector. The life history and 

 morphology of the tick have been reported handsomely by Curtice 



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