MOSQUITO WORK IN 1908. 80 1 



These may be made straight, or may curve to follow the natural 

 drainage of the land, as seems best. The only requisites are that 

 the bottom of the ditches be fairly smooth, and have enough 

 fall so as to leave no places for the water to stand in pools. The 

 edges should also be kept fairly clean. 



Notes regarding a few details are as follows : 



There is a depression ten or fifteen feet across, at the side of, 

 and partly under, the bridge where the driveway crosses at the 

 south end of the range. The bottom is more or less covered with 

 rocks, between which the water stands. Water was present here 

 June 24th, just after a long dry period. No mosquito larvae found 

 at this time. On August 12th larvae of both Anopheles and 

 Culex were present in small numbers. Filling the depression with 

 dirt to the top of the rocks would make it safe. 



A short distance north is a large brush-covered pondhole, which, 

 though dry at the time of both examinations, would probably hold 

 water even in a normally wet season. It will require a ditch 

 several feet deep to drain it across the skirmish run. If this 

 forms too much of an obstruction a tile or covered drain could be 

 constructed. 



Northeast from the building occupied by the quartermaster's 

 department a low area extends inland from the main stream, 

 in which is much standing water. Grass and weeds occur here, 

 and it is more or less obstructed by fallen trees and brush. 

 Anopheles larvae were present August 12th. A wide ditch could 

 be dug here, and the material used to fill, so as to make abrupt 

 edges. These should be kept clean, so that the fish will be able 

 to reach the edges. 



To the north is a low area which can be easily drained. 



Towards the north end of the range is an old choked ditch 

 which should be cleaned out if there is any standing water in the 

 vicinity. 



The edges of the main stream should be kept clean from any- 

 thing that would obstruct the fish, and any other places where 

 water stands should be drained or filled as recommended above. 



It would be hard to estimate the cost of eliminating all breeding- 

 places, but to carry out the above recommendations, using simply 

 open ditches, would probably cost less than one hundred dollars. 

 Tile drains would of course cost much more, and are not necessary 

 to do away with all possible mosquito breeding-places. 



