THE MOSQUITOES OF THE SOUTHEASTERN STATES 23 
erties are definitely known, it is true that dense vegetation is attractive 
to many species of mosquitoes as a harboring place. This is probably 
due to the moisture and shade afforded by the vegetation, as well as to 
protection from winds. Some of the woods mosquitoes are also known 
to bite commonly in shady places during the daytime but will not fly 
into the open for a blood meal. 
Adult mosquitoes have various natural enemies, such as certain 
birds, bats, and predacious insects, which prey upon them along with 
other insects. The erection of bat roosts in mosquito- infested areas 
has been urged as a means of control, but observations in places where 
bats are very numerous have shown that they have little effect in 
reducing the mosquito population (87). 
SPECIFIC PROBLEMS 
A few notes are given below in regard to problems of control of 
some of the more Important species. 
THE COMMON MALARIA MOSQUITO (ANOPHELES QUADRIMACULATUS) 
This species develops principally in permanent bodies of fresh 
water containing aquatic vegetation or floating debris (pls. 1-3). 
Because of the breeding habits of this mosquito, malaria in the South- 
ern States is largely a disease of rural communities and small towns. 
Malaria control in this region usually consists of measures against 
Anopheles quadrimaculatus, the first essential of which is the perma- 
nent elimination of the low swampy places by filling or drainage. 
This species does not ordinarily fly long distances, and the control 
of the breeding places within a mile of a populated area is thought 
usually to be effective (6, 59, 109, 111). Ditches and the margins of 
the deeper ponds and lakes should be kept free of vegetation, and 
breeding in shallow ponds full of aquatic growths or in the beds of 
occasionally flowing streams can sometimes be controlled economically 
by impounding the water with dams to a depth sufficient to overcome 
the aquatic vegetation (pl. 8, B). Periodic fluctuation of the water 
level in such impounded areas is important in reducing the marginal 
growth and flotage. The impoundage of large bodies of water for 
hydroelectric or other purposes, however, has introduced serious prob- 
lems in malaria control, and special legislation has been enacted by 
southern States covering the measures that must be taken to prevent 
breeding of anopheline mosquitoes in such projects. The Tennessee 
Valley Authority has found it necessary to provide for an extensive 
program of Anopheles control in the impounded areas on the Tennes- 
see River (76). As this work has progressed it has proved essential 
to establish minimum requirements as to reservoir preparation and 
shore-line improvement, with special reference to vegetation control, 
and to provide for adequate water-fluctuation schedules i185 Ll) 
As previously mentioned, in planning extensive drainage opera- 
tions careful consideration should be given to problems of wildlife 
and soil conservation. 
The use of chemical larvicides, such as oil and paris green, 1s _re- 
quired for treating breeding areas that cannot be eliminated, ‘and in 
many places, owing to local conditions, this constitutes the main part 
of the control program. Paris green dusted on the water will destroy 
