THE MOSQUITOES OF THE SOUTHEASTERN STATES 33 
Although little is known of the extent to which this species feeds 
upon wild animals, man and most of the domestic animals are known 
to be attacked by the blood-hungry females. Information on the 
relative attractiveness of different hosts was obtained in a series of 
cage experiments conducted in Baltimore, Md. (35, 39). Two host 
species were exposed side by side to the bites of Anopheles quadrimacu- 
latus females, which were afterwards collected and the blood meals 
identified by the precipitin test. Among cattle and horses it was 
found that the attractiveness varied more between individuals than 
between the species, and that a decided variation also occurred between 
individuals of the human race. The latter received on an average 
about one-sixth as many bites as the horse or cow. Sheep, goats, dogs, 
and pigs appeared to be less attractive, in the order given, while 
rabbits and chickens proved to be very poor hosts even in the absence 
of other animals. 
To determine the proportion of mosquitoes that obtained blood 
meals from different hosts under natural conditions, a large series of 
records had previously been obtained at Mound, La., by testing the 
blood from freshly fed females collected from the tenant dwellings 
and outbuildings on three plantations (702). From a general series 
of collections during the mosquito season of 1922, 38 percent of the 
specimens taken inside the house were found to have fed on man, 
and about 2 percent of those from underneath the house and in the 
outbuildings. The weighted average was 4.3 percent for the entire 
quadrimaculatus (female) population, being 6 to 8 percent when the 
average number of females per location was about 200 to 500 and 
decreasing to 3 percent or less when the average reached 1,500 or more. 
The average percentages for the other hosts for which blood tests 
were made were as follows: Cow, 36; horse, 33; pig, 16; dog, 8; and 
other animals (chicken and cat), 3. 
Although very high malaria infection rates (10 percent or even 
more) have been found among anophelines in other countries, the 
percentage of infected guadrimaculatus in malarious areas in this 
country appears to be comparatively low, probably much lower than 
is generally supposed. From an examination of 9,340 specimens col- 
lected on plantations in the vicinity of Mound, La., in 1922 (97), 
only 10 were found to contain the sporozoite form of the parasite in 
the salivary glands and therefore to be capable of transmitting the 
infection at the time of capture. This gave a sporozoite rate of 0.107 
percent, or approximately 1 infective specimen per 1,000. The annual 
malarial rate in humans on the same plantations during that year was 
about 45 cases per 100. At Edenton, N. C., a gland-infection rate 
of 0.383 percent was obtained from dissections of 1,486 mosquitoes over 
a period of 3 years (2/). 
The larvae of Anopheles feed almost entirely at the water surface, 
and since they seem to make no selection of material provided it is 
small enough to be ingested, the food consists of the general variety 
of small organisms that are found at the water surface. From a 
large series of observations at Mound, where guadrimaculatus was 
the predominant anopheline, Bradley (37) reported that flagellates, 
diatoms, and the green algae made up a large proportion of the 
plankton content of the surface layer in the natural waters of that 
