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

MOSQUITO REDUCTION 61
and careful so as to avoid serious experiences later when con-
trol measures are under way.
(3) A topographical map of the control area should be
carefully prepared.
The three propositions above stated are essential to the out-
lining o,f control activities. How can they be carried out? Suc-
cessful control depends on scientific knowledge. Mosquitoes,
either in the adult or larval stages, can be determined only by
those who know them-not by those who think they know them
or believe that all mosquitoes have the same habits. In carry-
ing out the first proposition, much data may be obtained on
breeding areas which can be located on the topographical map.
But omitting all factors but the first one for the present, let
us see the problem in its true relation to the problem of con-
trol. The species that are mainly responsible can usually be
collected during an outbreak. If it proves to be the common
house mosquito (C&x pipiens), the types of breeding grounds
are well known and control measures are indicated. If it proves
to be Aedes z~exa.xs, a different breeding ground is assured and
other control measures must be applied. If the main outbreaks
are due to the early sprin, u species, as Aedcs stimulam, A. ex-
cmciam, A. fitchii, etc., another type or types of breeding places
must occur in or near the area. If anophelines are present in
numbers, then still other types of breeding grounds prevail and
other methods of control are indicated. If the main outbreaks
are due to such migratory forms as TmGorhyzclzzw pertzwbam,
Aedes znexans, Aedes sollicitans, A. canhtor, or A. tavziorlzyz-
clzzts, the problem becomes more complicated.
The second step is necessary in order that the species breed-
ing in the area surrounding the district under control may be
known. If migratory species breed here steps will have to be
taken to reduce the breeding areas as much as possible.
The third step may be combined to a great degree with the
first if determinations are made from the larvae. Every part
of the area should be carefully mapped, all standing water,
streams, ponds, cisterns, wells, catch basins, etc., should be