52 MALARIA 



Anopheles wrigglers are usually found in great abun- 

 dance (Fig. 22). 



As a rule, the least suspected places (as far as the 

 average person is concerned) are the most dangerous. 

 Large open ponds and larger streams are not, as a rule, 

 directly concerned, though each individual case needs 

 careful inspection before allowing it to pass. Such 

 seemingly small matters as a little spring in a pasture, 

 a hoof print, a leaky faucet, a bad kitchen drain, 

 waste water from a laundry, notwithstanding its soap 

 and lye content, a leaky irrigation ditch, — ■ these are 

 the greater nuisances that the inspector has to meet. 

 Prospecting holes (Fig. 23), tin cans, water barrels, 

 tubs, etc. (Fig. 24) must not be overlooked. Very 

 often the water in the street gutters (Fig. 25) is a pro- 

 lific source of Anopheles mosquitoes, notwithstanding 

 other observations to the contrary. 



