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PACIFIC SCIENCE, Vol. Ill, April, 1949 
formed quite readily at a temperature of 11° 
to 12° C. and persisted for at least 6 days. 
Several experiments were conducted to test 
the developmental ability of the pigeon Haemo- 
proteus in local mosquitoes. In all cases the 
mosquitoes were reared from larvae and pupae 
collected in the field. Adult females were fed 
on moist raisins for at least 2 days and were 
then kept from both food and water for another 
2 days before their first blood meal. They were 
liberated into a cage 30 inches high, 28 inches 
wide, and 32 inches deep for feeding on in- 
fected pigeons. Feathers were plucked from 
about the body of the pigeons to expose the skin 
and to allow greater opportunity for engorge- 
ment by the mosquitoes. No difficulty was en- 
countered in getting a sufficient number of 
engorged mosquitoes for the observations de- 
scribed below, although apparently many of the 
females did not feed on the pigeons. All ex- 
periments were conducted at room temperature, 
which fluctuated between 62.5° and 83.5° F. 
during this period. 
Experiment I: (1). On February 5, starved and 
thirsty females of Culex quinquefasciatus Say were 
liberated into the cage containing an infected pigeon 
with 250 gametocytes of Haemoproteus columbae per 
10,000 red cells. The mosquitoes were allowed to 
feed overnight and engorged females were collected 
the next morning, placed in a small cage, and main- 
tained on moist raisins. The engorged individuals 
were presumed to have had one blood meal during 
the night. 
(2). Ten females were dissected on February 15, 
10 on February 17, 5 on February 21, and 10 on 
March 10. All of these examinations showed midguts 
negative for Haemoproteus oocysts. 
Experiment 11: (1). On April 30, starved and 
thirsty females of C. quinquefasciatus were liberated 
into a cage with a pigeon showing 175 gametocytes per 
10,000 red cells. These mosquitoes were allowed to 
remain in the cage with the pigeon throughout the 
experiment and some of the engorged individuals 
presumably had more than one blood meal. 
(2). Fifteen females were dissected on May 9, and 
18 on May 16 with completely negative findings. 
Experiment III: (1). On May 8, 10 starved and 
thirsty C. quinquefasciatus females were liberated into 
a cage with a pigeon showing 250 gametocytes per 
10,000 red cells. 
(2). On May 9, after about 18 hours, all of these 
females were dissected with the following results: 
four females showed no evidence of having taken a 
blood meal; six females were partially to completely 
engorged and stomach smears treated with Giemsa’s 
stain showed many gametocytes of Haemoproteus 
columbae still within red cells and some exoerythro- 
cytic rounded macrogametocytes. S^me extracellular 
Fig. 2. Globular forms of macrogametocytes of Haemoproteus columbae after breaking 
out of red cells. (A) Smear of heparinized blood from infected pigeon. Note that one 
gametocyte is just breaking away from red cell. (B) Smear from midgut of Aedes 
albopictus one hour after engorging on infected pigeon. (Smears treated with Giemsa’s 
stain. Photomicrograph by Dr. G. B. Mainland; slightly retouched.) 
