94 N. J. Agricultural Experiment Station, Bulletin 348 



to consideration, the time of collection should be between 7.30 p. m. 

 and 9 p. m. Each collector should spend at least 15 minutes in a place 

 and one man may take care of two or even three places. 



If the territory is large and the number of collectors small, one 

 evening each week should be given to the county-wide collection and 

 various limited portions of the territory should be attended to on the 

 other evenings. . 



The number representing each species at each station should be 

 determined on the following morning and the results set down upon 

 a map of the area. If here and there over the map small isolated 

 areas where mosquitoes are much thicker than elsewhere are found, 

 these areas should without delay be most carefully searched for 

 overlooked breeding. If areas of considerable size are found on 

 the border or of large size well within the confines of the area, they 

 should at once be further studied. If the species concerned belongs 

 to the salt-marsh or fresh-water swamp or woodland-pool, daylight 

 collections will serve to get at the facts, but if the house forms are 

 to blame the examinations will have to be made in the evening. In 

 either case, two lines of collection should be made — one running 

 through the dense zone in one direction and the other at right angles. 

 The direction in which the number of mosquitoes caught grows 

 larger is the source of the brood and if the tracing is done promptly 

 the larvae or pupae or pupal shells will be found where the brood 

 in question matured. If not promptly traced the location of the 

 source of brood may be found to be impossible. 



It is thought that by use of these methods of collection the density 

 of the mosquito fauna may be expressed in terms of so many 

 mosquitoes a minute or other period of time, and that the number 

 per minute, quantities above which mean trouble to the householder 

 and below which mean freedom from trouble, will soon be determ- 

 ined for each of the species concerned. It is thought that experience 

 will soon define the increase in number, which means that the fresh- 

 water species, especially the house mosquito, is breeding unchecked 

 and that more careful examination must be made. It is further 

 thought that this increase may be detected early enough so that the 

 breeding may be found and eliminated before the density of the 

 fresh-water mosquito fauna becomes sufficient to trouble the house- 

 holder. It is thought that the practice of these methods will enable 

 the exterminator to run down accurately the breeding places from 

 which the invasion of migrational mosquitoes come and thus to take 

 the first necessary step toward their elimination. 



