I20 AGRICULTURAL EXPERIMENT STATION. 



and diffuses more quickly through the water. Both materials 

 mix with the water and may be very greatly diluted without 

 losing their effectiveness; but the Phinotas oil has disinfecting 

 properties and stands a very much greater dilution. It is the 

 most effective larvicide known to me, and for sewer catch basins 

 it has no equal. It should be applied with a gardener's syringe 

 through a fine rose nozzle, and two ounces will be abundant for 

 the ordinary city catch-basin. The syringe distributes the mate- 

 rial evenly over the surface, economizes the oil and should be 

 used for all the substances suggested. If a syringe is not availa- 

 ble, a sprinkling pot with a fine rose will answer. Work on 

 catch basins need not begin, ordinarily, until the last w-eek in 

 May and need not be done until four or five days after a heavy 

 rain that has flooded the basins. Under ordinary conditions ten 

 days may be allowed to elapse before- another treatment is made, 

 and if then or thenabout a heavy shower flushes the basins, they 

 are safe for at least five days more. In ordinary seasons, with a 

 normal amount oi rain, no more than half a dozen and perhaps 

 even fewer treatments will be necessary. It must be a matter 

 of discretion with the officer in charge to- select those periods 

 when, with a brood of larv^ae approaching maturity, he can kill 

 them off and gain safety for a week tO' come. 



Cesspools, where they occur, should be completely covered, 

 or if ventilated, should have a wire screen over the mouth of 

 the opening. If it be for any reason impossible to cover com- 

 pletely, a liberal application of Phinotas oil will ensure safety 

 for a long time. Fuel oil will evaporate slowly and will main- 

 tain a safe film for two or three weeks. 



Manure pits should be dealt with as are cesspools, save that 

 no Phinotas oil or other germicide should be used. The fuel oil 

 is best here, provided a tight cover cannot be maintained. 



The drainage system in parks where there is an overflow from 

 lakes or ponds or where the surface water is carried off through 

 pipes should be especially well looked after, because breeding is 

 even more free there than in the sewer basins of a city. In Cen- 

 tral Park, New York City, Dr. Berkeley, Mr. Seal and myself 

 found under every grating that we lifted larvae, of this species 

 in the settling pool. Mr. Brehme found the same condition of 

 affairs in Branch Brook Park, at Newark. 



Gutters kept in proper repair and properly graded can never 

 become dangerous ; but gutters used as receptacles for house 

 waste, broken or defective so that water lodges in them, form 

 excellent breeding places. Where the gutters are unpaved or 

 mere grooves or shallow ditches partly choked by vegetation, 

 mosquitoes find a congenial home for their larvae. For such 



