Haemoproteus of Pigeons — Kartman 
131 
microgametocytes were noted, but a diligent search 
failed to show definite evidence of exflagellation. 
All the rounded gametocytes were morphologically 
similar to those found in smears made from hepar- 
inized pigeon blood ( see Fig. 2 ) . No ookinetes were 
seen and most of the gametocytes were intracellular 
and typical halter forms, indicating probable im- 
maturity. 
Experiment III also included observations on Aedes 
albopictus ( Skuse ) . Starved and thirsty females of 
this species were liberated into the cage on May 8 
along with the other culicine described above. Two 
of these females were dissected 1 hour after feeding 
on the infected pigeon and stomach smears showed 
a few rounded macrogametocytes. On May 9, about 
20 hours after being placed in the cage, five engorged 
females were dissected. Stomach smears again re- 
vealed some rounded macrogametocytes. Ten addi- 
tional females were dissected on May 15 and 15 more 
were examined on May 23. All midguts were nega- 
tive for oocysts. 
As in the case of Culex quinquefasciatus, the 
stomach smears of A. albopictus showed a few 
rounded macrogametocytes, some extracellular micro- 
gametocytes, and many halter forms still within in- 
tact red cells. No ookinetes were noted. 
Experiment IV: An attempt was made to infect the 
hippoboscid fly ( Olfersia aenescens Thomson ) , which 
is normally found on ocean birds. The flies used were 
collected by employing a juvenile red-footed booby, 
Sula sula rubripes, as a decoy. About 3 6 0. aenescens 
were brought to the laboratory on February 28. Ten 
were dissected the next day and were found negative 
for evidence of oocysts on the midgut. On February 
29, 20 of these flies were liberated in a cage with an 
infected pigeon showing 230 gametocytes of Haemo- 
proteus columbae per 10,000 red cells. Most of the flies 
seemed attracted to the lighter side of the cage and 
were not apparently interested in the pigeon. Several 
flies were found dead on each succeeding day and 
none was seen flying about the cage after 7 days. On 
March 10 the pigeon was removed from the cage 
and only one O. aenescens was recovered from it. 
Dissection of this fly showed fresh blood in the mid- 
gut, but there was no evidence of oocyst formation. 
Experiment V: Four puparia were collected from 
the captive Olfersia aenescens described above. At 
room temperature two of these hatched in from 52 
to 53 days, but the others failed to emerge. The two 
flies were placed on an infected pigeon on April 24, 
and both immediately ran underneath the feathers. 
On May 4 these two flies were taken from the bird 
and dissected with negative findings. 
SUMMARY 
1. Observations have been made on the halteri- 
dium parasite of the pigeon, Haemoproteus 
columbae Kruse, 1890, in pigeons from lofts 
at the Honolulu Zoo. 
2. The hippoboscid vector, Pseudolynchia can- 
ariensis (Macq. ), was found to be present 
at an average rate of 2.0 per bird on about 
50 juvenile pigeons and 1.3 per bird on 100 
adult pigeons. Of 45 doves examined, none 
harbored this fly. 
3. Of a total of 25 P. canariensis dissected, 9 or 
36.0 per cent were found to be naturally in- 
fected with the pigeon Haemoproteus . 
4. Of 101 adult pigeons examined by the blood 
smear technique, 83 or 82.2 per cent were 
positive for Haemoproteus columbae. Of 43 
doves examined, none was found infected 
with the pigeon parasite or any other blood 
protozoan. 
Fig. 3. Left: Oocyst of Haemoproteus columbae on midgut of Pseudolynchia canariensis. Approx. 
950 X. Right: Oocysts of H. columbae on hindgut of P. canariensis. Approx. 440 X. 
