84 
MAT.ARTA 
waters near the coast. The tropical species 
A. albimanus, whose range extends into the 
United States in southern Texas, is said to 
occur at times in salt marshes in the tropics. 
Attempts at a specific classification of 
the breeding places of Anopheles in this 
region have been made chiefly for the three 
common species occurring in the Southeast¬ 
ern States, A. quadrimaculatus, A. puncti- 
pennis, and A. crucians. Owing to the 
paramount importance of A. quadrimacu¬ 
latus as a malaria vector, most of these 
studies have been made to determine the 
factors correlated with the presence or ab¬ 
sence of this species in various environ¬ 
ments in order that such factors may be 
evaluated for control purposes. 
Temperature. Temperatures of anophe- 
line breeding waters in North Carolina 
were analyzed by Boyd (1929b), who con¬ 
cluded that A. quadrimaculatus breeds in 
the warmer waters having a rather limited 
diurnal range, whereas A. punctipennis 
chooses waters that either are distinctly 
cooler or have a wide variation in diurnal 
range. These differences were especially 
noted in the fall when breeding of A. 
quadrimaculatus was definitely limited to 
the warmest places. As the temperatures 
decreased, this species was replaced by A. 
punctipennis in many locations. A. cru¬ 
cians was found to require water as warm 
or warmer than those required by A. 
quadrimaculatus, and this is evidently cor¬ 
related with the more southerly range of 
the species. Boyd also states that a mean 
temperature of 70° F or higher appears 
to be essential for the rapid evolution of the 
stages of A. quadrimaculatus, and notes 
that the northern limit of the distribution 
of this species coincides closely with the 
July isotherm of 70° F. The range of A. 
punctipennis extends much farther north. 
Barber and Komp (1929c) found the latter 
species in waters in which the temperatures 
went well above 100° F during the day¬ 
time, although the fact that it is commonly 
found in springs and shaded pools and has 
a wider distribution in the cooler seasons 
indicates a preference for lower tempera¬ 
tures. Barber and Forbrich (1933) distin¬ 
guish two extreme types of anopheline 
breeding waters in northern New Mexico, 
those having cool waters at all times of the 
day, which produced A. freeborni exclu¬ 
sively, and those wholly exposed to the sun, 
in which A. pseudopunctipennis usually 
occurred in “pure culture.” They con¬ 
clude that day-time temperatures seem to 
be the determining factor in these cases, 
although cold springs far up in the moun¬ 
tains if exposed to the sun were found to 
contain A. pseudopunctipennis. 
Hydrogen-ion concentration. The pref¬ 
erence of A. quadrimaculatus and A. punc¬ 
tipennis for alkaline breeding waters and 
of A. crucians for acid waters is quite well 
established. Boyd (1929b) reported that 
larvae of A. quadrimaculatus and A. punc¬ 
tipennis in both Georgia and North Caro¬ 
lina have but rarely been found in waters 
having a pH lower than 6.1 and never in 
those below pH 5.1. Breeding waters of A. 
crucians were usually on the acid side of 
neutrality, but never below 4.6 or more 
alkaline than 8.0. The mean pH values for 
the breeding waters in North Carolina were 
found to be approximately 7.06, 7.10, and 
5.24 and in Georgia 7.46, 7.32, and 6.99 for 
A. quadrimaculatus, A. punctipennis, and 
A. crucians, respectively. The Georgia rec¬ 
ords show breeding waters there to be gen¬ 
erally alkaline, but the bulk of breeding 
waters of A. crucians was slightly acid. 
In northeastern Louisiana, where A. 
quadrimaculatus was the predominant 
anopheline, Bradley (1932) found the 
breeding waters to range from pH 6.8 to 
9.2. Watson and Spain (1937) state that 
spring-fed lime sink ponds having a mean 
pH of 7.2 and a range of 6.5 to 7.8 more 
nearly approximate the ideal breeding 
place of A. quadrimaculatus than do any 
other waters in northern Alabama. An 
extensive series of observations has been 
made by Leg wen and Kirby (1939) to de¬ 
termine the feasibility of employing hydro¬ 
gen-ion determination as' an index to the 
breeding of A. quadrimaculatus in connec¬ 
tion with larvicidal control operations. In 
most of the work reported it is not stated 
whether the determinations were made in 
