THE NORTH AMERICAN CATTLE TICK. 1138 
greatly lengthened. In one case a tick which dropped on November 
20 did not begin depositing until January 25, giving a preoviposition 
period of 66 days. As a rule, however, the adults are killed by tem- 
peratures which are sufficiently low to retard deposition to this 
extent. The following table, which is based upon ticks which 
Fig. 7.—The North American cattle tick, Margaropus annulatus: Distribution in the United States. 
(Original. ) 
dropped from the host, shows an oviposition period of from 1 to 3 days 
and a deposition period of from 8 to 16 days. The average number 
of eggs deposited by the 10 ticks was 3,424 and the maximum 
number deposited by one female was 4,547. 
21448°—Bull. 106—12——8 
