4 BULLETIN 147, U. S. DEPARTMENT OF AGRICULTURE. 
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 in 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. 
