54 
lake was changed froma body of fresh toa body of salt water. Water 
that is somewhat brackish will support mosquitoes, but Tes which 
is purely salt will destroy them. 
‘* Practical use of jish.—The introduction of fish into fishless breeding 
places is another matter. It may be undesirable to treat certain 
breeding places with kerosene, as, for instance, water which is intended 
for drinking, although this has been done without harm in tanks 
where, as is customary, the drinking supply is drawn from the bottom 
of the tank. An interesting case noted in Insect Life (Vol. IV, 
p- 223), in which a pair of carp was placed in each of several tanks, 
in the Riviera, is a case in point. The value of most small fishes for 
the purpose of destroying mosquito larvee was well indicated by an 
experience described to us by Mr. C. H. Russell, of Bridgeport, Conn. 
In this case a very high tide broke away a dike and flooded the salt 
meadows of Stratford, a small town a few miles from Bridgeport. 
The receding tide left two small lakes, nearly side by side and of the 
same size. In one lake the tide left a dozen or more small fishes, 
while the other was fishless. An examination by Mr. Russell in the 
summer of 1891 showed that while the fishless lake contained tens of 
thousands of mosquito larve, that containing the fish had no larve. 
‘‘Theuse of carp for this purpose has been mentioned in the preceding 
paragraph, but most small fish willansweras well. The writer knows 
of none that will be better than either of the common little stickle- 
backs ( Gasterosteus aculeatus or Pygosteus pungitius). ‘They are small, 
but very active and very voracious. Mr. F. W. Urich, of Trinidad, 
has written us that there is a little cyprinoid common in that island — 
which answers admirably for this purpose. This fish has not been 
specifically determined, but we hope to make an effort to introduce it 
into our Southern States, if it proves to be new to our fauna. At Bee- 
ville, Tex., a little fish is used for this purpose, which is there called a 
perch, although we have not been able to find out just what the species 
is. -They soon eat up the mosquito larve, however, and in order to 
keep them alive the people adopt an ingenious flytrap, which they keep 
in their houses and in which about a quart of flies a day is caught. 
These flies are then fed to the fish. This makes a little circle which 
strikes us as particularly ingenious and pleasant. The flytraps catch 
the flies and rid the house of that pest. The flies are fed to the fish in 
the water tanks and keep them alive in order that they may feed on 
the mosquito larve, thus keeping the houses free of mosquitoes. 
“Artificial agitation of the water.—Where kerosene is considered 
objectionable, and where fish can not be readily obtained, there is 
another course left open. It is the constant artificial agitation of the 
water, since mosquitoes will oviposit only in still water. At San 
Diego, Tex., in the summer there are no streams for many miles, but 
plenty of mosquitoes breed in the water tanks. Some enterprising 
