98 MONTANA EXPERIMENT ISTATION 



vented the ticks from being thrown beyond the pan when the guinea 

 pigs shook. Six of these cages were used and were found to be 

 satisfactory. No one of the three persons who worked in the same 

 room during the summer found any ticks on his body or clothes dur- 

 ing the season. We used the above described cages instead of the 

 form we had seen in use by Dr. Ricketts as we wished to closely 

 watch the guinea pigs and ticks during the experiments. With 

 infected ticks the form used by Dr. Ricketts would probably be more 

 desirable. 



For the sake of reducing to a minimum the amount of urine xrt 

 the pans it was found to be best to feed the guinea pigs but little 

 gieen food of a-siicculent nature. Roots and oats are more desirable 

 than such food as dandelion leaves. 



The collars used were of the sort described by Dr. Ricketts. 



The following tables show the dates on which ticks were put 

 i;;to cages, the number put in each, with the dates, and the dates, 

 of recovery of engorged ticks. 



Unfed larvae put in cage. 

 July 9—70 

 July 17 — 450 (estimated.) 



Unfed larvae put in cage. 

 July 11— 30 

 July 13— 30 

 July 17 — 450 (estimated.) 



Unfed larvae put in cage. 

 July 13— 30 

 July 16— 30 

 July 17—450 (estimated) 



