6o The Control of Mosquitoes 



time to become thoroughly acquainted with the 

 conditions peculiar to his district, that each day's 

 work may produce the maximum of effective 

 results. In time he becomes expert in omitting 

 much that is but apparently necessary, 



STREAMS 



Large and small streams and natural water- 

 courses, although dry for several months of the 

 year, often become important propagation areas. 

 Their relative importance or output of adults 

 varies with the season. As a rule, during the wet 

 season larvae are found in quiet places along the 

 banks where vegetation occurs or overhangs the 

 banks or where debris collects. It seems to 

 be an instinct of the Anopheles to lay her eggs 

 where there will be a maximum of protection, or 

 hiding places, and of food supply for her brood. 

 Small detached bodies of water adjacent to the 

 stream are favorable; and where the banks are 

 muddy, the footprints of those looking for larvae 

 may become filled with water by seepage from the 

 stream, and later contain larvae. Where the water 

 is quiet or shallow, green algae develop rapidly 

 and by retarding the current assist the Anopheles. 

 These places offer favorable harboring places for 

 larvae. 



