5 
and Gambusia affinis are all extremely important enemies of the 
mosquito larvee. 
As the writer was concerned primarily with the salt-marsh mos- 
quito, his problem was to discover what species of fish was most 
effective on the marshes, both ditched and unditched. While the 
work herewith recorded is largely from Middlesex and Monmouth 
Counties, the excellent report system of the Entomologist and the 
willing cooperation of the many chief inspectors and inspectors ex- 
tend the records throughout the entire State. 
In the following pages we shall show that not only is Pundulus 
heteroclitus the most voracious enemy of the larve, pup and adults 
of the mosquito, but that on account of the migration habits, numbers 
and supremacy of the species, it is the most important natural factor 
in the extermination of the salt-marsh mosquito. It is worthy of 
note that Funduls heteroclitus is also an important enemy of the 
ereen-headed_ fly. 
PooLs AND STREAMS UNDER OBSERVATION 
In order to study the fish closely and extend the period of ob- 
servation under natural salt-marsh conditions, a marsh near Bon- 
hamtown, New Jersey, and about three miles from the City of New 
Brunswick, was selected as the chief station for study. Here collec- 
tions were made at intervals from September 19, 1914 to August 15, 
Lt. 
3 
Fig. 1.—Diagram of sall-marsh area showing pools from which fish 
were taken. Scale: 1 inch -12 feet. 
