94 AGRICULTURAL EXPERIMENT STATION. 



As the tide moves in over the marshes or flats, these fishes move 

 with it in unbroken Hne Hke a heavy Hne of battle, feeding as they 

 go. The chance of a mosquito larva escaping them is infinites- 

 imal. Any waters to which these fishes have free access will be 

 searched in vain for mosquito larva. An exception must always 

 be made of places where there are dense masses of aquatic plants 

 coming to the surface, over which, in fresh water. Anopheles will 

 harbor. Unfortunately all the species of Pimditlus which throng 

 the coast and rivers of New Jersey attain a length of from four 

 to six inches, and it is the young alone that can be depended on 

 to penetrate in any great numbers to the furthest limits of tide 

 flow." 



No one can properly appreciate the importance of these little 

 fish who has not seen the swarming mass of wrigglers in the salt 

 pools containing none of them and the freedom of these where 

 even a few killies are found. To be sure larvae are sometimes 

 found with the little fish ; but then, either the larvae were so 

 numerous that the fish simply could not eat them all or the fish 

 were so small that they could not manage the full grown larvae. 



An impressive example of their usefulness is cited by Mr. 

 Brehme : In the morning at low water he crossed the Newark 

 meadows to the shore and found all pools fairly swarming with 

 larvae and pupae — millions upon millions. During the day the 

 tide rose to an unusual height, covering the marshes almost to 

 the highland. In the early evening on his return to the city, re- 

 crossing the marsh, he found killies in all the pools and larvae and 

 pupae scarce. Next day on further examination he found the 

 brood almost completely wiped out. Almost every little hole had 

 one or more of the fish and the larvae had disappeared. 



In 1903 one of my cage experiments was spoilt in the same 

 way. The cages were set just below the edge of the highland, 

 but well beyond the reach of all ordinary tides. While the pools 

 within the cage were fully stocked, the tide rose to an unusual 

 height and fish found their way through the openings between 

 sill and marsh into the cage itself. When the cage was next vis- 

 ited only the fish were left. 



During 1904 tides ran low, and it was the absence of the usual 

 overflows that permitted the marshes along the coast to develop 

 the enormous first broods that flooded the country in Ma}^ and 

 June. Usually the bulk of that brood forms fish food. Besides, 

 the winter of 1903-04 was so unusually severe that a very large 

 percentage of the fish were killed ofif. 



Several times during the seasons of 1903 and 1904 Mr. 

 Brehme transferred killies from ditches to pools swarming with 

 larvae, and in everv instance it was onlv a matter of hours before 



