80 
inland form) has also been reported as 
attacking in sunlight as well as in shade, 
the attacks beginning as early as 7:15 a.m. 
(Mayne 1926b). The species is, in fact, 
referred to in the Middle Atlantic States 
as the daylight anopheline. A. maculipen- 
nis is said by Freeborn (1926) to bite 
viciously in bright sunlight on becoming 
active in the spring. 
Adult activities are dependent on tem¬ 
perature probably more than on any other 
factor. The optimum biting temperature 
for anophelines was found by Mitzmain 
(1919) to be between 28 and 30° C and 
the minimum between 16 and 17° C. A 
sudden rise in temperature is said by Mayne 
(1926a) to stimulate the blood-seeking im¬ 
pulse. Boyd (1930a) states that on moon¬ 
light nights the period of activity of 
anophelines is extended. Before heavy 
rains they are particularly voracious and 
some species enter houses at night in larger 
numbers than usual at such times. Heavy 
rains also may cause fewer mosquitoes to 
be on the wing, but they become active 
again soon after the rains cease. 
Rudolfs (1923) found that mosquito 
activity, as determined by the numbers 
alighting to bite, increased with the rela¬ 
tive humidity up to 85 per cent, above 
which no change was noted in mosquito 
behavior. Freeborn (1932) states that 
there is a midsummer depression in the 
abundance of A. maculipennis in California 
due to high temperatures and low humidi¬ 
ties. During this period the females of the 
second and third generations live only long 
enough to deposit eggs but not long enough 
to permit malaria transmission. Maximum 
daily temperatures in excess of 33° C and 
evaporation from a white ball atmometer in 
excess of 70 cc occur during this season. 
Blood feeding. So far as known the food 
of female anophelines primarily is blood, 
and a blood meal appears necessary for the 
maturation of eggs. The females, however, 
may subsist for long periods in captivity on 
fruit juices or sirup, and it has been con¬ 
cluded by Boyd (1930a) that the pursuit of 
blood not only satisfies a whim of appetite 
but arouses the mating instinct as well. 
While male mosquitoes often alight on 
warm-blooded animals and probe around 
with the proboscis, they are unable to pierce 
the skin. They subsist on water, nectar, 
and fruit juices. 
The different species vary considerably 
in their host preferences. Bull and Rey¬ 
nolds (1924) and Bull and Root (1923), in 
comparing horses and cows as hosts for A. 
quadrimaculatus, showed experimentally 
that attractiveness in the hosts varied more 
among individuals than among species. 
Humans, although varying individually 
also, received on the average only one-sixth 
as many bites as horses or cows. Sheep, 
goats, dogs, and pigs appeared to be less 
attractive in the order given, while rabbits 
and chickens were very poor hosts even in 
the absence of other animals. 
King and Bull (1923) determined the 
blood-feeding habits of A. quadrimaculatus 
in nature by identifying the blood meals 
from a large series of females caught in 
various locations. They found that an 
average of 38 per cent of those taken inside 
houses had fed on man, but only 2 per cent 
of those taken in outbuildings. The 
weighted average was 4.3 per cent for the 
entire female A. quadrimaculatus popula¬ 
tion, being 6 to 8 per cent when the average 
number of females per location was about 
200 to 500 and decreasing to 3 per cent or 
less when the average reached 1,500 or 
more. The average percentages for the 
other hosts for which precipitin tests were 
made were as follows: Cow 36, horse 33, pig 
16, dog 8, and chicken and cat 3. These 
observations indicate quite definitely that 
certain animals, horses and cows particu¬ 
larly, have a greater attraction for A. 
quadrimaculatus than has man, so some 
degree of protection from bites must be 
afforded when such animals are available. 
In these experiments the blood meals of a 
few A. punctipennis and A. crucians were 
also tested. Of 79 A. punctipennis none 
had fed on man, and of 125 A. crucians 6 
contained human blood. 
Attraction to lights. Anophelines are 
attracted to artificial lights, and most of 
our species have been taken in light-trap 
