i8o N. J. Agricultural Experiment Station, Bulletin 348 



Experiment 3 



OBJECT. To determine the minimum dosage of nitre cake for Culex 

 pipiens. 



Using the same solution as in experiment 1, two additional dilutions were 

 added as follows : 



0.5 gm. of nitre cake in 1,000 cc. of .tap-water. 

 0.25 gm. of nitre cake in 1,000 cc. of tap-water. 



Fifty larvae of Culex pipiens were placed in each jar at 9:30 a. m., July 

 14, 1917. Twenty minutes afterward, all larvae were dead in the 50-gm. solu- 

 tion. At 11:00 a. m., July 14, 1917, an examination was made of all jars 

 with the following results : 



All larvae dead in the 25-gm. solution. 

 50 per cent dead in the lo-gm. solution. 

 10 per cent dead in the i-gm. solution. 



All were alive in the 0.5-gm. and 0.25-gm. and check solutions. 

 On July 15, 1917, the jars were examined with the following results: 

 All dead in the lo-gm. solution and above. 

 5 alive in the i-gm. solution. 

 10 alive in the 0.5-gm. solution. 

 43 alive in the 0.25-gm. solution. 

 46 alive in the check. 

 An examination of these jars was made at 9:00 a. m. July 16, 1917, with the 

 following results : 



All dead in the lo-gm. solution and above. 

 One live pupa and 4 pupal shells in the i-gm. solution. 

 15 live pupae in the 0.5-gm. solution. 

 40 larvae and pupae alive in the 0.25-gm. solution. 

 46 larvae and pupae alive in the check. 

 Experiments 4 and 5 were designed to determine the minimum 

 dosage for the white-banded salt-marsh mosquito, which was selected 

 as a type of the salt-marsh forms. 



Experiment 4 



OBJECT: To determine the minimum dosage of nitre cake for Aedes 

 sollicitans. 



Solutions of nitre cake in salt-marsh creek-water (2% salinity) were made 

 as follows : 



25 gm. in 1,000 cc. 

 10 gm. in 1,000 cc. 

 I gm. in 1,000 cc. 

 0.5 gm. in 1,000 cc. 

 0.25 gm. in 1,000 cc. 

 None in 1,000 cc. 

 Fifty larvae of /Irdcs sollicitans were placed in each jar at 10:45 »• m-. J^^y 

 14, 1917. At 12:15 1). ni. the following results were observed: 



