lOG 



commenced to loosen at the margins and curl upwards. At eight 

 on the following morning a single example only was found capable 

 of slight motion. 



Experiment '2.— This was a repetition of the first experiment with 

 identical results except that all the plant lice examined on the 

 naorning of the 19th were absolutely dead. 



Experiment 3. —In this case the same solution was applied to an 

 infested leaf with a camel's hair brush with the same effects, all the 

 bark lice being dead at eight the following morning. 



Experiment 4. — On the 22d of the month a two and a half per 

 cent, dilution of the kerosene emulsion was thrown with a force 

 pump and a tubular nozzle upon a branch of a soft maple tree. 

 The leaves were not as thoroughly wetted as desirable. Four days 

 after about half the young bark lice were alive, although it is pos- 

 sible that the branch treated had been restocked by young from 

 other parts of the tree, as the insects were still moving about and no 

 precaution had been taken to prevent such migration. 



Experiment 5. — On the same day a branch of soft maple attached 

 to the tree was dipped in a two and a half per cent, dilution of 

 kerosene, and on the following day three-fourths of the bark lice 

 were dead. Four days after a few were still alive, but not enough 

 to do any appreciable harm, and another application would doubt- 

 less have killed them all. 



Experiment 6. — On the 29th the same experiment was tried with 

 a five per cent, dilution of kerosene, the emulsion being made with 

 whale oil soap, and common soap suds being used for dilution. Two 

 days later the bark lice remaining on the leaves of this branch were all 

 dead. 



Experiment 7. — On the 29th, on the other hand, an application 

 was made to a branch by dipping m a two and a half per cent, 

 dilution, soap suds being again used as the diluent, and live days 

 thereafter no considerable diminution in the number of living bark 

 lice was apparent. It seems likely, however, considering the length 

 of time that had elapsed between the experiment and the observa- 

 tion, that the branch had been restocked by young from other parts 

 of the tree, as the lice were still actively crawling about. 



Experiment 8. — On the 31st of the month the leaves of a branch 

 of soft maple which was stocked with young bark lice were dipped 

 in a five per cent, dilution of kerosene emulsion like that used in 

 the preceding experiment. Five days later a few living bark lice 

 still occurred upon the leaves, but nearly all had disappeared. 



Experiment 9. — On the 6th August a similar experiment was 

 made with a similar fluid, but containing ten per cent, of kerosene. 

 The branch treated was not examined until nine days afterwards. 

 The leaves were not at all injured by a solution of this strength. 

 Many bark lice still remained upon them, but they had perhaps 

 been restocked with living young. 



In all the preceding observations tke effect upon this bark lice 

 was determined by microscopic examination, the sign of death relied 



