172 The Control of Mosquitoes 



to kill mosqtiito larvae spoils water for use for 

 domestic or industrial purposes. 



For certain purposes, however, oil is very useful, 

 and in the absence of a more acceptable larvacide, 

 the sanitarian must depend largely upon it. 



The defects of oil were soon recognized in 

 Panama, and persistent efforts made to find a 

 more desirable larvacide. The product named 

 "larvacide" in Panama was thus introduced, and 

 although short of perfection, is under many condi- 

 tions superior to oil. 



