THE TICKS 145 



6. Amblyomma atnericanum. The Lone Star Tick. — Amblyomma 

 (p. 142). — The body is oval and in color yellowish gray or brown. 

 When not distended, the body-surface is rough and puckered. Festoons 

 are present. The scutum extends backward a short distance to form a 

 triangle, at the apex of which is a white or yellowish spot, from which 

 the tick derives its name "Lone Star." The mature female may reach 

 a length of one-half an inch. The legs are long and thin. 



This species has been found on cattle, dogs, horses, sheep, goats, hogs, 

 and man. It is very widely distril)uted in the United States. 



All of these ticks show longitudinal grooves ujion the dorsal surface 

 of the body which are most distinct a few days after the tick's repletion 

 and removal from the host. These furrows vary considerably in different 

 members of the same species and, though some authors appear to attach 

 importance to them, they can hardly be considered of much value as an 

 aid in recognition. Color is also unreliable in the identification of 

 genera and species, as this varies with the stages in the tick's develop- 

 ment and may change variously in adult ticks of the same species. 



The Texas-fever Tick. — Kilborne, of the Bureau of Animal Industry, 

 proved conclusively by field experiments conducted in 1889 and 1890 

 that it is only through the bite of this tick that Texas-fever can be 

 naturally transmitted. Economically, therefore, Margaropus annulatus 

 (Plates I and II), the Texas-fever tick, is the most important for con- 

 sideration. Other ticks not concerned in the transmission of Texas- 

 fever have been mentioned here as occiu'ring upon cattle, all having 

 the same successive stages in their development, namely, oval, larval, 

 nymphal, and adult male and female. Before molting and transforming 

 from one stage to the other these ticks fall from their host, after the 

 transformation seeking a new host. That this is not true in the case 

 of the Texas-fever tick was shown by Dr. Cooper Curtice, of the Bureau 

 of Animal Industry, in 1891. He established the fundamental facts 

 in the life history of this tick and showed that it remains upon its host 

 from the time that it attaches as a larva until it drops to the ground 

 replete and ready to deposit its eggs (Tables, p. 151). Careful observa- 

 tions by the Zoological Division of the Bureau have supplied valuable 

 data relative to the biology of this tick, and much detailed information 

 has been published by the Bureau pertaining to this and to tick control 

 and eradication. In this connection, it may be of service to mention 

 here the following titles, any of which can be obtained upon application 

 to the Superintendent of Documents, Government Printing Office, 

 Washington, D. C. 



Texas Fever, Methods for its Prevention, by John R. Mohler. Bull. 

 No. 78 (1905). 



Texas or Tick Fever and its Prevention, l)y John R. Mohler. Farmers' 

 Bull. No. 258 (1906). 



