CONTROL OF MARSH MOSQUITOES 391 



Eeferring again to the breeding of mosquitoes in catch-basins or sewer-traps, 

 it was shown as early as 1900 by Mr. T. Pergande, of the Bureau of Entomology, 

 that the common rainwater-barrel mosquito breeds in small sewer-traps in the 

 rear of houses in southeast Washington. He determined this point by putting 

 a gauze screen over the sewer-trap in his own yard and finding adult mosquitoes 

 under the screen, morning after morning. Of late years, in practically all the 

 city of Washington, and in fact, notably in the northwest section, where is to 

 be found the better class of residences, and where the general conditions are such 

 as to preclude the possibility of the breeding of mosquitoes in other places, sewer- 

 trap bred mosquitoes are very annoying, especially during the dry spells in 

 July, August and September. At one time the city catch-basins, located at 

 the comers of the streets, were flushed at least once in ten days, under the orders 

 of an efficient official in charge of sewers for the District of Columbia. This 

 procedure, if fully carried out, would prevent the breeding of mosquitoes in 

 these basins. The private catch basins, usually situated near the kitchen door, 

 are not under city control and are so constructed as to hold water indefinitely 

 and to permit the breeding of a lesser number of mosquitoes during a protracted 

 dry spell. It is easy to avoid this breeding by putting a small cupful of kero- 

 sene into the sewer trap at intervals of from ten days to two weeks. But the 

 difficulty arises that during the months in question, in the northwest quarter 

 of the city, many houses are closed for the summer, and the treatment of the 

 catch-basins on the premises of temporary absentees can only be accomplished 

 by someone in authority, as a sanitary inspector, for example. Malarial mos- 

 quitoes occasionally breed in these catch basins, as one of us (Dyar) found two 

 larvae of Anopheles in a small catch basin in the yard of his premises during 

 August, 1912. They were easily removed by flushing the drain. 



REMOVAL OF BROMELIACEOUS PLANTS. 



Sir Eubert Boyce, in his " Mosquito or Man ?," calls especial attention to 

 the wild pines or Bromeliaces as breeding places of mosquitoes in the American 

 tropics, and to the extraordinary numbers in which these epiphytes occur in 

 certain localities. He states that one Saman tree, which was cleaned up for the 

 purpose of destroying mosquito breeding-places, yielded 26 cart-loads of these 

 epiphytes whose total weight was 3.62 tons. He shows that each plant may hold 

 from ten to twenty ounces of water and that the total volume of water repre- 

 sented by these parasites of a single tree was probably equivalent to a good-sized 

 pond, 



DRAINAGE MEASURES AGAINST NON-DOMESTIC SPECIES. 



The drainage of swamp areas for agricultural or other industrial reasons 

 needs no argument nor treatment here. The value of reclaimed swamp land for 

 various purposes is treated somewhat in extenso in an earlier section, " Value 

 of Eeclaimed Lands." The drainage of swamp areas primarily in order to im- 

 prove sanitary conditions and to reduce the annoying scourge of mosquitoes, 

 which in itself frequently prevents the proper development of neighboring 



