4 BULLETIN 147, U. S. DEPARTMENT OF AGEICULTUEE. 



experimental cattle they were picked off, and the seed ticks derived 

 from them became available about August 1. From that time on 

 there was an abundance of material. 



The time of application of the ticks may be roughly divided into 

 two periods, viz, from June 4 to July 28, in which ticks were applied 

 at intervals of seven or eight days, and from August 1 to September 

 25, in which they were applied on each alternate day with but two 

 exceptions. The effect of weekly applications was to cause the ticks 

 to ripen in groups covering about five days; the alternate day appli- 

 cations caused a more continuous and intense infestation. The exact 

 fluctuations of this were not determined on account of cessation of 

 gathering ticks when sufficient had been obtained to complete the 

 experiment. 



Collections of ticks from the experimental cattle were made twice 

 daily during milking time from June 26 to September 4. This was 

 necessary in order to obtain seed ticks for a continuation of the experi- 

 ment into the fall months. The deleterious effects of the ticks were 

 less than if they had been allowed to mature on the cattle; but in 

 such case future seed ticks would not have been available. Addi- 

 tional effort to acquire material from other sources demonstrated the 

 futility of depending upon outside sources for seed ticks. As the 

 experiment proceeded it became too late to employ other cows for 

 raising ticks, a plan which would be better if the experiment were to 

 be repeated. 



The count of the ticks made and given in an appended table does 

 not include all that became attached to the cattle, for some dropped 

 off, some were picked off by chickens, and others were licked off by the 

 cattle themselves. Also many incompletely mature ticks were col- 

 lected which might have added their share of damage to that already 

 produced. Table 1 contains the number of ticks picked from each 

 cow daily, the dates when they were applied, and their source. The 

 infestation during the earlier period, June 4 to August 5, was practi- 

 cally like a fall infestation hi intensity, excepting that the ticks were 

 not maturing equally throughout the week, thus causing milder 

 effects during the time that the ticks matured less rapidly. Infesta- 

 tion on different cows was from slight to gross during the whole ex- 

 periment. Under farm conditions pasture infestations may occur 

 daily, thus making continuous appearances, such as occurred during 

 only a part of the week in the experiment, and producing consequently 

 more severe injuries. The collecting of ticks was continued until 

 within 30 days of the close of the experiment, when the supply was 

 sufficient to maintain infestation until the completion of the work. 



