Insects and Parasitic Diseases. 101 



rangle lawn. The bag, which was 15 in. from the ground, was 

 exposed to all prevailng weather conditions, as in Experiment No. 

 29. The range of temperature was the same as in the preceding 

 -experiment (No. 32). Three young Louse-flies emerged on the third 

 •day, one on the twelfth day, one on the sixteenth day, five on the 

 nineteenth day, one on the twenty-fourth day, one on the twenty- 

 sixth day, and one on twenty-seventh day. The remaining thirty- 

 eight pupae Avere found to be dead on December 31st. 



Thus 31.5% of the pupae remained viable, and produced young 

 from three to twenty-seven days from the date of their removal from 

 the host. 



Experiment No. S^.. 



Sixteen pupae collected on August 6th were placed on moist earth 

 In a Petri dish, which was kept in a cool dry cellar beneath the 

 Institute building. Throughout the experiment the earth was kept 

 in a moist condition. During the first tw^enty-five days the tem- 

 perature ranged from 50°F. to 59°F., and during the remaining 

 period of the experiment (forty-five days) the range was from 52 °F. 

 to 60^ F. None of the pupae produced young flies, and all were 

 found to be dead when examined seventy days after the experiment 

 was commenced. 



Experim^ent No. 35. 



An experiment similar to the above, in which twenty-six pupae 

 of unknown ages, placed on dry earth, was commenced also on 

 August 6th. None of the pupae produced young flies. 



Experiment No. 36. 



One hundred and eighty pupae, collected on January 9th, wiere 

 kept on the laboratory bench in a 4 oz. tobacco tin, containing a 

 small quantity of wool. The tin was covered with its lid except 

 when it was necessary to open it for the purpose of counting the 

 young flies. During the experiment the maximum temperature was 

 90°F. and the minimum 60°F. The pupae were examined on the 

 •days mentioned, and the young ** ticks " were removed from the 

 tin on these occasions. Two young '* ticks " were removed at the 

 end of the first day, eight on the third day, sixteen on the sixth day, 

 seven on the eighth day, eleven on the ninth day, eight on the tenth 

 day, twenty-seven on the twelfth day, three on the fourteenth day, 

 seven on the seventeenth day, ten on the twentieth day, five on the 

 twenty-second day, six on the twenty-third day, four on the twenty- 

 .seventh dav, three on the thirtieth dav, five on the thirtv-first dav. 



