PRINCIPLES OF MOSQUITO CONTROL 285 



control is definitely the dominant species. It appears to be more prac- 

 ticable to bring the salt marsh species under control than it is to get the 

 best of the house mosquito. The reason for this condition lies in the na- 

 ture and location of the breeding places of the two groups. The breed- 

 ing of the salt marsh species occurs in the open away from human habi- 

 tation and inspection reveals the conditions that must be met. The 

 breeding of the house group occurs in water accumulations everywhere 

 about, on and in human dwellings and places of business. 



Thus far no scheme of inspection and treatment of the house mos- 

 quito group, which does not enlist the willing aid of the householder or 

 factory manager, has been successful in securing and maintaining con- 

 trol. 



The swamp mosquito group, consisting of Aedes vexans and Man- 

 sonia perfurbans pass the winter in the egg and larval stages respec- 

 tively. The group breeds mainly but not entirely in the wilds. Vexans 

 shows a great range of breeding places, ranging from the typical fresh 

 water swamp through backyard lot pools to enclosed and low salinity 

 salt marshes nor does it refuse to breed in water polluted with human 

 wastes. 



The perturbans habit of breeding only in permanent soft bottom 

 pools and swamps, never rising to the surface for air, renders it immune 

 to ordinary surface filming larvicidal applications. 



The fresh water swamp group has considerable migratory ability. 

 Movements of ten to fifteen miles are not uncommon but here as else- 

 where it is the largest and densest broods that go farthest. 



The removal of water by drainage, filling or impounding with bot- 

 toms dug to depth to prevent aquatic vegetation from growing in it and 

 finally stocking these waters with wriggler-eating fish, will eliminate the 

 breeding of both these species. Temporary treatments with larvicide 

 will destroy vexans but, of course, will not reach perturbans. From 

 Florida, comes the suggestion that cutting off the tops of aquatic plants 

 below the water surface destroys the perturbans larvae attached to 

 their roots. 



The woodland pool group, consisting of Aedes canadensis, Aedes ab- 

 fitchii, Aedes trivittatus, Aedes triseriatus, and Aedes hirsuteron pass 

 the winter in the egg or egg and larval stages. This group breeds in the 

 wild lands and ordinarily does not migrate to any considerable extent. 

 So much of the woodland of northeastern New Jersey has been taken up 

 for suburban homes that these comparatively nonmigratory species 

 have been brought in sharp contact with human kind. 



Contrary to all preceding species, except perturbans, the woodland 



