148 PARASITES OF THE DOMESTIC ANIMALS 



The Cattle Tick in its Relation to Southern Agriculture, b}^ August 

 Mayer. Farmers' Bull. No. 261 (1906). 



Proceedings of a Conference of Federal and State Representatives 

 to Consider Plans for the Eradication of the Cattle Tick. Bull. No. 97 

 (1907). 



Methods of Eradicating Cattle Ticks, by Louis A. Klein. Cir. No. 

 110 (1907). 



Studies on the Biologv of the Texas-fever Tick, bv H. W. Gravbill. 

 Bull. No. 130 (1911). 



Methods of Exterminating the Texas-fever Tick, by H. W. Graybill. 

 Farmers' Bull. No. 498 (1912). 



Progress and Prospects of Tick Eradication, by Cooper Curtice. 

 Cir. No. 187 (1912). 



Texas or Tick Fever, by John R. Mohler. Farmers' Bull. No. 569 

 (1914). 



Life History; the Nonparasitic Development. — The following data 

 as to the life histor}^ of the Texas-fever tick is taken from Graybill 

 (Studies on the Biology of the Texas-fever Tick, 1911). The non- 

 parasitic development is considered bj^ this author under five periods, 

 namely, the preoviposition period, the oviposition period, the incu- 

 bation period, the hatching period, and the longevity period of the 

 larva? . 



The period of preoviposition extends from the time the female tick 

 drops until she begins to deposit her eggs. In a series of investigations 

 carried out at Auburn, Ala., m 1907-8 it was observed that the average 

 duration of this period ranged from three to forty-nine and three-tenths 

 daj^s, depending largely upon temperature, the shorter average period 

 occurring in August, the longer in December. 



The average oviposition or egg-Iaymg period for different months of 

 the year ranged from eight and three-tenths daj^s for June to one hun- 

 dred and twenty-seven and five-tenths daj^s for November. The 

 maximum period noted was one hundred and fift^^-two days, observed 

 in November, and the mmimum three days, observed in June. The 

 maximum number of eggs deposited by a female tick was 5105, minimum 

 357, with an average ranging from 1811 to 4089. 



The incubation period was found to range from nineteen days in the 

 summer to one hundred and eighty days beginning in the fall. The 

 conditions essential to development and hatching are moisture, such as 

 supplied bj^ sufficient atmospheric humidity to prevent eggs losmg 

 moisture by evaporation, and a favorable temperature. 



The hatching period is taken as the time required for all of the eggs to 

 hatch after hatching begins, the eggs deposited by a female hatching 

 approximately in the sequence in which the,y are laid. The average 

 period was found to range from ten and six-tenths days for Jul.v to 



