132 AGRICULTURAL EXPERIMENT STATION. 



with a small amount of the water in which they were breeding' 

 and some of the bottom or food material, in three jars of city 

 water, to which copper sulphate enough was added to give the 

 following proportions : 



Jar I — I part of copper sulphate in 1872 of water. 

 Jar 2 — I " " " " " 976 " " 



Jar 3—1 '• •• •• " " 624 " " 



This experiment began at 2 P. M., and during the afternon 

 the larvcT remained in apparent good health ; but at 8 A. M. next 

 morning- all were dead. The larvae in a check jar were doing 

 nicely when this experiment ended. 



Bxperiment 2: with full grown larvae and pupae of Culex can- 

 tat or collected in brackish water on the Newark meadows. 

 They were placed together, with some of the bottom or food 

 material and a small amount of breeding- water, in three jars of 

 city water. Three days later, adults having begun to emerge, 

 copper sulphate enough was added to give the following propor- 

 tions : 



Jar I — I part of copper sulphate in 3587 of water. 

 Jar 2 — I " " " " " 1873 " 



Jar 3- — I " " " " " 1292 " " 



Eighteen hours after the addition of the copper sulphate the 

 larv^ and pupae were in apparently healthy condition. Forty- 

 two hours thereafter the conditions were unchanged. After 

 sixty-four hours the pupee were active and hatching, but the 

 larvae were dead, except for two in Jar i and one in Jar 2. 

 Ninety-six hours after it began conditions had not changed and 

 the experiment was closed. 



Bxperiment y. with full g-rown larvae and pupae, mostly C. 

 pipiens, collected at Vailsburg-. Together with a small amount 

 of food material and breeding water, they were placed in eight 

 jars of city water, to which copper sulphate was added to give 

 the following proportions : 



Jar I — I part of copper sulphate in 4382 of water. 



" " " 2072 " " 



" 996 " 



" 727 " 



" 577 " 



" 456 " 



" 297 " 



" " " 219 " " 



Eight hours after the addition of the copper sulphate the 

 larvae and pupae were in an apparently healthy condition and the 



