June, '14] HEADLEE: A\TI-MOSQUITO WORK IN NEW JERSEY 265 



has the most pecuHar larval life of the more important species. It 

 breeds in places that partake of the nature of a woodland pool and 

 of a swamp. The larvae never come to the surface for air; but remain 

 for their entire life among the grass roots at or near the bottom of 

 the pool. 



Beginning in late April the woodland species get on the wing and 

 continue to be troublesome to persons living near or penetrating 

 their haunts until midsummer, when they almost cease to be noticed. 

 When breeding places for Aedes sylvestris Theob., the swamp mosquito, 

 are present it wall appear with the woodland species and stay for the 

 rest of the season. 



The house mosquito usually begins to appear in troublesome num- 

 bers in late June and by the middle of July is abundant, and continues 

 so until cold wxather stops its breeding and sends it into winter quar- 

 ters. We usually think of this species as migrating only a few 

 hundred yards, but the work of the past summer has indicated that 

 w^hen bred over a large area in enormous numbers it infests adjoining 

 territory for nearly or quite 2.5 miles. 



Inasmuch as this fact, in the writer's belief, is being formally re- 

 corded for the first time, the proofs upon which it rests should be set 

 forth with some care. 



The entire territory included in the counties of Union and Essex 

 was under constant observation throughout the last two mosquito- 

 breeding seasons. With the exception of the Ebling marsh, which 

 lies to the southeast of the City of Newark, the mosquito breeding 

 in Essex and Union Counties was under such good control, that an 

 expert would have to search this territory for some time before he 

 found pupae of fresh water breeding mosquitoes. About fifty acres 

 of the Ebling meadow, w^hich was waterlogged with sew^age, began 

 breeding Culex pipiens Linn, and Culex salinarius Coq., about mid- 

 summer and continued throughout the season with the exception 

 of certain periods wdien extra high tides cleared the sewage out suffi- 

 ciently for "kilJifish" to penetrate or the efforts of the Essex County 

 Mosquito Extermination Commission resulted in the destruction of 

 a brood. 



The southern part of the City of Newark and the northern part 

 of the Cit}^ of Elizabeth exhibited a far larger number of mosquitoes 

 (both C. pipiens and C. salinarius, but mainly the former) than did 

 other parts of these counties. This concentration was practically 

 coincident with the heavy breeding on these sewage-charged marshes. 

 The pupae were just as difficult to find in the districts heavily infested 

 as they were in districts in which there were not enough mosquitoes 



