a handbook of the mosquitoes of north america - Systematic Catalog ...

62 MOSQUITOES OF NORTH AMERICA
accurately located on a large scale rnap.l All such places, par-
ticularly the ponds, streams, bayous, swamps, etc., should be
carefully described so that changes of personnel will not delay
the work.
When the above information is at hand a definite plan for
the ultimate reduction and elimination of breeding grounds
may be undertaken. Any plan will depend largely on local
conditions, the extent and character of the breeding grounds
and the species of mosquitoes involved. The only known
methods now available are drainage operations, filling and grad-
ing, keeping the banks of streams and large ponds clear of
marginal and floating vegetation, employment of surface feed-
ing fishes, oiling operations, and the use of poisons. Any plans
evolved should be in co-operation with all the other agencies
which have to do with s&anitation, city or rural planning com-
missions, departments df public works, etc., and such work
should be under the immediate direction of the agency dealing
with public health. It is too early yet to hope for the States
or provinces to undertake large scale operations unless it is in
particularly malarious regions and then only in co-operation
with the national governments. When the co-operation of all
public bodies and the citizens of a given area can be obtained,
plans should be carefully prepared and continuity of activity is
essential from year to year.
TYPES OF CONTROL OPERATIONS
When a plan for mosquito reduction has been evolved, suit-
able for the area under consideration, particular attention
should be paid to the various methods of control. A few of
these may be briefly outlined here.
in
Drainage
When the known breeding areas are fairly well determined
a given district, those that can be drained or greatly reduced
‘Such maps can be obtained by enlarging the topographical maps
of the Geological Survey.