48 AGRICULTURAL EXPERIMENT STATION. 



appearing to be rarely the case), the sedge march becomes just as virulent as 

 black grass, and is also reduced to a stubble in chronic areas. 



"The genera of grasses here named do in a general way hold to their re- 

 spective territory; though one invades the other's ground quite frequently. 



"Cat-tail, Typha, grows in fresh water and fills in thoroughfares, etc., when 

 cut off from the sea. If it be filled with rain-water, such a cat-tail marsh is 

 made dangerous by interrupted drainage, though inland it seems to be quite 

 free from mosquito breeding. The marsh-mallow. Hibiscus, grows also in 

 places prone to breed mosquitoes. 



"Taking into consideration the flora, the most serious breeding places can 

 be located as well in dry as in wet weather. 



"The salt hay zone extends along the edge of the highland everywhere along 

 the coast. Wliere grading has been done the remaining depressions, filled 

 with salt hay, can be readily recognized, and will breed all the marsh species." 



Not least among the breeding places are those created by man's 

 interference with natural drainage. I know of numerous cases 

 where streets, roads or avenues have been built through a safe, 

 well-drained area without reg-ard to existing conditions, leaving 

 as the result on one side of the road a stagnant swamp area, 

 without outlet for surface waters, which was bound to and did 

 grow up into a veritable paradise for Culex pipiens and its allies, 

 as well a^ Anopheles. Only a little consideration by the engi- 

 neers in charge would have prevented all this without much if 

 any additional cost. This sort of artificially created breeding 

 place is by no means peculiar to New Jersey, and affords an illus- 

 tration of the fact that results aimed at may be obtained with the 

 addition of results not contemplated or desired. 



Railroads are great offenders in this direction. Their aim is, 

 usually, to get a road-bed at the least possible cost and drained 

 so as to leave a dry surface as far as possible out of reach of 

 storm effects. When on a comparatively level stretch or in a 

 cutting, the road-bed is usually a little higher than the regular 

 surface level and a shallow ditch takes the surface water from 

 the railroad track level. What becomes of the water after it gets 

 into this ditch is not considered unless the quantity endangers 

 the road. It may and often does lie for days and weeks, afford- 

 ing ideal conditions for several species of Culex and the common 

 species of Anopheles. 



In fact, there is scarcely a railroad ditch draining a road-bed 

 that does not breed mosquitoes, and in at least half the cases 

 there is no real necessity for allowing the water to stagnate at 

 all. It could have been disposed of by the engineer from the 

 beginning if the desirability of doing so had occurred to him. 

 There are numerous cases in the State where parallel roads leave 

 a depression between their rights of way from which water is 

 rarely absent and where mosquito breeding- goes on unchecked. 

 The same disregard of natural drainage when road-beds are run 

 through a low or swampy area that characterizes the usual road 



