10 The Control of Mosquitoes 



quito-producing areas, and their relation to the 

 malaria situation, has been fully appreciated by 

 those engaged in anti-malaria work. Beginners 

 usually learn facts by temporary failure. Soon 

 after the completion of this work the adult Anoph- 

 eles disappeared from the vicinity. No new cases 

 of malaria occurred. The houses that had been 

 so long vacant because of the prevalence of malaria 

 were again occupied. When it became known that 

 malaria no longer existed in that locality, it was 

 plotted into lots, and has become one of the popu- 

 lar residential sections of the town. Real estate 

 values have advanced accordingly. 



On low fiat lands where cattle were pastured, it 

 was fotind difficult to prevent Anopheles propaga- 

 tion in the water retained by hoof -prints. It be- 

 came essential to prevent certain portions of fields 

 from being used for grazing purposes during the 

 wet season. 



It was also found that plants along the shore 

 line, as well as aquatic plants, reduced the surface 

 velocity of water in streams and rivers to such an 

 extent as to afiford protection and harboring 

 places for mosquito larvae. The vegetation at the 

 edges of ponds and streams was kept cut short. 

 Aquatic vegetation was pulled up by the roots and 

 removed. Small fish were very efficient larvse 



