136 
instances, malaria in mountainous sections 
of the Eastern United States is associated 
with artificial lakes since the terrain pre¬ 
vents extensive natural collections of still 
water. A few cases of malaria have been 
found associated with Lake Norris since its 
impounding in 1936. The impounding of a 
small lake in Putnam County, Tennessee, 
caused an epidemic of malaria in 1925. 
These situations are in the foothills of the 
Cumberland Mountains, at an altitude of 
about 1200 feet. 
In general, the distribution of A. maculi- 
pennis is more northern than A. quadri- 
maculatns, although Hinman and Hurlbut 
(1941) found both species occurring to¬ 
gether in Southern Ontario. It is found 
principally West of the Rocky Mountains, 
from Southern California to Alaska, and 
Eastward through Canada to Northern 
Maine. Its natural history, including its 
requirements for prolific propagation are 
quite similar to that for A. quadrimacu- 
latus. The larvae are found in permanent 
or semi-permanent collections of water, 
such as roadside pools, along the margin of 
lakes and in irrigated fields. However, it 
accommodates itself better to the colder cli¬ 
mates of high altitudes than does A. quadri- 
maculatus. It has been reported to occur 
in the Valley of Mexico at altitudes up to 
8000 feet (Bustamente 1939). Boyd 
(1940f) has observed malaria due to A. 
maculipennis near Reno, Nevada, at an 
altitude of 4000 feet. 
Anopheles albimanus is the principal vec¬ 
tor of malaria in the Greater Antilles, 
Mexico, and Central America at elevations 
less than 3000 feet. This species exhibits a 
great adaptability to diverse environmental 
situations, perhaps more than any other 
mosquito in North America. While it pre¬ 
fers stagnant water which is exposed to 
direct sunlight, it may be found along the 
margins of flowing streams and in marshes 
containing brackish water. Perhaps the 
greatest deterrent to its propagation is 
dense shade. Its occurrence is not re¬ 
stricted entirely to lowlands, although, in 
general, it does not find favorable situations 
for propagation at altitudes considerably 
above sea level. It probably utilizes small, 
temporary collections of water to a greater 
extent than does A. quadrimaculatus, such 
as cattle tracks in seepage areas. 
Anopheles tarsimaculatus occurs through¬ 
out the Lesser Antilles and on the mai nl and 
from Nicaragua southward. Its breeding 
situations are like those of A. albimanus 
and it exhibits much of the same adaptabil¬ 
ity of the latter mosquito to varying con¬ 
ditions. While its breeding places are usu¬ 
ally found at sea level, it may occur at 
altitudes up to 3000 feet (Root and An¬ 
drews 1938). 
A. pseudopunctipennis occurs in the semi- 
arid and arid portions of tropical and sub¬ 
tropical America from the Southwestern 
United States to Northern Argentina. In 
the United States it is apparently not of 
much concern in the transmission of ma¬ 
laria but in the highlands of Mexico and in 
Central America it is probably the prin¬ 
cipal vector. The available evidence sug¬ 
gests that this species has at least two races 
or subspecies, the lowland form being rela¬ 
tively innocuous. Its larvae are found in 
pools in stream beds during the dry season, 
in roadside ditches and in irrigated fields, 
such as the rice fields of Mexico. 
Until recently A. darlingi was thought to 
occur only in Brazil, but in the past two 
years has been found in various situations 
in Central America (Kumm 1940c). It is 
likely that it has a wider distribution than 
was believed formerly. This may be ac¬ 
counted for by the fact that the morpholog¬ 
ical characteristics of the adults are not 
unlike those of A. argyritarsis and may 
have been mistaken for this mosquito or for 
other white-footed species which occur in 
tropical America. Its detached occurrence 
in British Honduras suggests importation 
(Boyd 1940f). Because of its remarkable 
potentialities as a malaria vector, its occur¬ 
rence anywhere is of considerable impor¬ 
tance. At the present time, its distribution 
in Central America and the conditions un¬ 
der which it is found have not been defined 
accurately. 
Regional Geology and Topography 
in Relation to Endemic Malaria 
1. The United States. In the eastern 
