400 MOSQUITOES OF NORTH AMERICA 



act shall not exceed three hundred and fifty thousand dollars. The Comptroller 

 of the State shall draw his warrant in payment of all bills approved by the 

 director of the State Experiment Station, and the Treasurer of the State shall 

 pay all warrants so drawn to the extent of the amount appropriated by the 

 Legislature. 



" 11. This act shall take effect November first, one thousand nine hundred 

 and six. 



" Approved April 20, 1906." 



This law was drafted only after the most careful observations by Doctor Smith 

 and his assistants, and after they had made themselves perfectly familiar with 

 the conditions existing in the salt-marsh area in New Jersey and with the exact 

 life-histories of the different species of mosquitoes involved, and also after pre- 

 liminary drainage work had been undertaken and carried to successful con- 

 clusion over part of the area without the assistance of State funds. 



Doctor Smith had found that three species, of approximately similar habits, 

 develop in the salt marshes of New Jersey and migrate inland for long dis- 

 tances — ^up to 40 miles in some instances — thus making local work on the part 

 of inland communities by no means perfectly eflBcient. Citizens' organizations 

 had, for example, done excellent work in the way of destroying household and 

 other fresh- water breeding mosquitoes, in South Orange, Summit, and other 

 inland tovnis ; but occasional inland migrations of swarms of salt-water species 

 necessitated the retention of house screens and discouraged the community 

 workers. The salt-marsh species, studied by Doctor Smith, are Aedes cantaior, 

 A. sollicitans, and A. tmiiorhynchiis. The former is the more northern and 

 earliest, forming the bulk of the specimens on the marshes north of the Earitan 

 Eiver. South of that point cantator makes an early brood only and sollicitans 

 is the abundant species during the rest of the season until late fall when cantator 

 sometimes reappears. He found that tceniorhynclius is never so common as the 

 others and is a midsummer species. All of these species lay their eggs in the 

 marsh mud, and Doctor Smith found that these eggs may retain their vitality 

 for three years, even if repeatedly covered with water. He found that every time 

 a marsh becomes water-covered some eggs hatch, and if the water remains long 

 enough the larvse reach maturity. 



To prevent these mosquitoes breeding in the marshes, a system has been 

 developed by which the force working under the State Entomologist makes deep 

 narrow ditches in the salt marshes by means of special machinery. These 

 ditches are 10 inches wide and generally 30 inches deep, the sides being per- 

 pendicular. The upper twelve or eighteen inches of the ordinary salt marsh is 

 peat or turf, and the water drains readily from it. Below this peat is sand, mud 

 or clay ; and at 30 inches a depth has been reached which is below high-water 

 mark and below the point at which vegetation is likely to start. The ditches 

 are placed from 50 to 200 feet apart, depending upon the character of the marsh, 

 but more often 200 feet apart than less. 



Anticipating the ultimate passage of a State bill, work of this character was 

 begun on the Shrewsbury Eiver in 1902, and at the present time the marshes 

 on both shores are drained in their full length. In 1903-4, the marsh areas 



