MOSQUITO INVESTIGATION IN NEW JERSEY. 285 



used to fill the small deep holes that would naturally drain most 

 slowly. Toward the end of the task in April, it became a race be- 

 tween the ditchers and the insects, which were beginning to pupate. 

 The ditchers won and the last pool was drained before the first adult 

 mosquito issued. It was interesting to watch a new ditch just opened 

 into tide water, flowing in a steady stream toward the outlet and 

 carrying a surface cargo of wrigglers and pupa?; and yet more inter- 

 esting was it to see the 'killies' at the ditch mouth, taking care of 

 every specimen that came out and gradually running up the ditch 

 to meet them. On these hundreds of acres of meadow not one of the 



Machine Ditching on the Newark Meadows, Summer, 1904. 



millions of mosquito larvse came to maturity. On the marshes to 

 the north and south where no work was done, the mosquito output 

 was phenomenal and the early summer of 1904 will be long remem- 

 bered. Not only the nearby cities and towns were sufferers, but the 

 insects actually crossed both ridges of the Orange Mountains in their 

 travels to the west, and swarmed in the hills about Paterson to the 

 north. And in all this the Shrewsbury River country was practically 

 free from mosquitoes and remained so all summer ! There were some 

 local fresh- water species that proved troublesome later in the season; 

 but these were dealt with as fast as their breeding places were located. 

 The marsh mosquitoes that had been the pest of previous years were 

 conspicuous by their absence. A yet greater work was done by the 

 City of Newark, where 3,500 acres of salt marsh were dealt with. Xo 

 results were apparent in 1904, because the heavy early broods were 

 allowed to develop unchecked; but the marsh is now dry except in a 



