212 INSECTS 



from organisms that float on the surface fihn. Its float- 

 ing habit enables it to hve in very shallow water, and in 

 places where no fish except the smallest top minnows can 

 follow. 



For breeding places the species of Anopheles select 

 moderately clean water, and prefer the grassy edges of 

 large pools, ponds or swamp areas, or the eddies or dead 

 comers of sluggish streams or ditches. They do breed in 

 lot pools, however, and even in rain barrels, pails or tin 

 pans. Cess-pools, sewage water or dirty gutters are not 

 attractive to them. 



Despite this difference in habit the larvae are as much 

 susceptible to oils as are those of Culex, and in the pupal 

 stage the differences are much less pronounced. While 

 in a general way, the species of Anopheles are referred 

 to as malaria carriers, not all of them are able to serve 

 as intermediate hosts. The most common and widely 

 distributed form known to be dangerous is A. maculi- 

 pennis, which has two fairly well-marked dusky spots 

 on each wing. 



None of the domestic or house mosquitoes are great 

 travellers, and they rarely fly for any considerable dis- 

 tance ; but there are species breeding in the salt marshes 

 along our coasts, both Pacific and Atlantic, that migrate 

 long distances inland, drifting with the wind twenty 

 miles or more in a single night. These species lay their 

 eggs in the marsh mud and winter in that condition. 

 The larvae, which resemble those of the house mosquito, 

 develop equally well in salt or fresh water, and mature 

 in about ten days from the date of hatching. In the egg 

 stage they may remain dormant for months and perhaps 

 for years. 



There are many other kinds of mosquitoes important 

 as nuisances, but not a menace to health, whose consider- 

 ation here would carry us beyond the scope of this essav. 



