INSECTICIDES. 



71 



insecticide. The larvae used in the earlier experiments were 

 obtained by the artificial incubation of the eggs. 



For the sake of brevity the results of the experiments are 

 presented in tabular form. The heading of each table states 

 the age of the larvae used, the poisons and amounts of each 

 to 150 gallons of water. The figures indicate the total num- 

 ber of larva? found dead on successive days. In each experi- 

 ment ten larvse were used. The check experiments afford 

 data concerning the normal death-rate of larva? feeding on 

 unpoisoned food. 



PARIS GREEN v. WHITE ARSENIC. 



Indoor Experiments, commenced Feb. 8, 1897. Larvae, in First 



Stage. 



Duplicate Experiment, commenced March 26, 1897. 



