410 Report of the Department of Entomology of the 



as 0.33 per ct. acid were fatal to the eggs. The eggs that failed 

 to hatch in these tests with carbolic acid became pale brown in 

 color, which discoloration occurred about the time the checks hatched. 

 Laboratory tests to determine the effects of carbolic-acid emulsion 

 on larva?: Test No. 1. — To ascertain the larvicidal value of car- 

 bolic acid, tests were made as follows: Larvae were immersed for 

 one hour in the emulsion at the strength indicated in the accom- 

 panying table and then placed on moist sand for later examination. 

 The insects used in these tests were classified according to size. 

 The " small " larvse were in the second instar, the " medium " 

 sized larvse were recently molted individuals of the third instar, 

 while the " large " larvse were mature individuals of the third instar. 

 The results of this series of tests are shown in Table I: 



Table I. — Effect of Different Strengths of Carbolic Acib on Maggots. 



Test No. 2. — To determine the effects of carbolic acid on mature 

 larvse of the third instar under field conditions, the following experi- 

 ment was made. The larvse were placed in a slight depression 

 in a rather dry soil for treatment, and after the mixture had been 

 applied at strengths indicated in the table they were then slightly 

 covered with earth. The effects of the treatment are shown in 

 Table II. 



