78 The Control of Mosquitoes 



any reduction. As time went on the density of 

 larv« increased. The observers studying the situ- 

 ation were bitten continuously by Anopheles of 

 both species while standing in the water in full 

 sunlight. The adult species present was chiefly 

 Anopheles tarsimaculata although Anopheles albi- 

 manus and Culex were very plentiful. This 

 was the only time or place on the Isthmus in which 

 Anopheles were known to come out into the open 

 and bite freely in full sunlight. 



This production area continued in existence for 

 several months and frequent analyses of the water 

 for sea water content were made. In places where 

 the larvae were very numerous the water contained 

 sixty per cent, or more of sea water and at times 

 above eighty per cent. 



Although the Anopheles tarsimaculata appears 

 to thrive best in salty water, yet the larvse have 

 been found in fresh water in small quantities, 

 and a few adults have occurred ten miles away 

 from water affected by tide water. 



METHODS OF DETERMINING THE PRESENCE OR 

 ABSENCE OF ANOPHELES LARV^ 



In general we may expect to find larvae in 

 relatively quiet water where aquatic growth, 

 vegetation, dead leaves, debris, and twigs have 



