MOSQUITOES IN GENERAL 29 



of European residents, the servants liavinf^ conscien- 

 tiously changed the flowers every mornino-, but with a cor- 

 responding lack of conscientiousness omitted to change 

 the water. I have found them breeding in an old tin tcj- 

 mato-can on the dumps in Washington. Mr. W. P. Seal, 

 of Delair, N. J., writes that he finds the larva? of mos- 

 quitoes in rain-filled hollows in apple, maple, and other 

 trees, often at a considerable distance from the ground. 

 Mr. Pratt has found them breeding in a liolloAv stump 

 near Bladensburg. Mr. Pergande has shoAvn that they 

 breed in the closed sewers in Washington, entering 

 through the perforated sewer-traps and emerging tli rough 

 the same holes. Mr. Matheson showed me an old disused 

 well which was covered with a board cover, but on lifting 

 the cover mosquitoes were found roosting on the under 

 side in large numbers. There was a crack in the cover 

 sufticiently large to admit them, and they smelled the 

 water below, worked their way through the crack and 

 bred in the old well. They will breed in all water-tanks, 

 and the cover must be absolutely tight, since gravid fe- 

 males are so strongly attracted by water that they will 

 work through a crack wdiicli seems almost too small to 

 admit their bodies. Dr. John B. Smith says that they 

 are found in New Jersey in great num])ers in the pitchers 

 of the pitcher plants of the genus S(irraccni((. 



These statements refer for the most part, if not entirely, 

 to the common mosquitoes of the genus Culex, which we 

 assume to be comparatively harmless from the disease- 

 carrying standpoint, but they indicate plaiid3^ that where 

 one's object is to rid a house or a neighborhood of mos- 



