24 
PACIFIC SCIENCE, Vol. V, January, 1951 
Since these commonly infected birds are 
widespread and numerous throughout the 
Hawaiian Islands, it seemed desirable to as- 
certain the role they play in the dissemination 
of the parasite. To determine this, the degree 
of infestation of Surinam roaches was estab- 
lished at (1) a heavily infested poultry farm in 
Waialae, Honolulu, Oahu; (2) a relatively 
clean poultry yard in Manoa Valley, Hono- 
lulu; and (3) a residential area in Waikiki, 
Honolulu. In all three places roaches were 
numerous. 
As shown in Table 3 the roaches from (1) 
harbored a large number of infective eye- 
worm larvae per roach. At (2), where low in- 
festation of the chickens resulted from strict 
sanitation and frequent removal of the ma- 
nure, but where large numbers of wild birds 
gathered to feed, the number of larvae per 
roach was very low. At (3), an area at some 
distance from any poultry farm, but where 
wild birds were also very numerous, no larvae 
were found in the many roaches examined. 
Inasmuch as domestic fowl and wild birds 
are the only sources of infection of the local 
roaches these data indicate that the local wild 
birds are of little importance as reservoir hosts 
in the dissemination of the eyeworm popu- 
lation. Apparently their feces are too scattered 
to be eaten to any great extent by the roaches. 
Mammals as hosts of Manson s eyeworm 
In no case has Oxyspirura mansoni been 
known to occur naturally in the eyes of a 
mammal. Fielding (1927) found that infec- 
tive eyeworm larvae placed in the eyes of 
guinea pigs would develop to maturity. 
To check Fielding’s observations on an- 
other mammal, I obtained several white rats. 
Each of these was forcibly fed four infected 
roaches. The next day the eyes were anes- 
thetized with a 5 per cent solution of butyn 
and examined carefully for eyeworm larvae. 
No larvae were found. 
Approximately 30 infective larvae were then 
introduced by pipette into the mouth of one 
of the rats. On examination of the eyes 24 
hours later, no larvae were found. 
Two rats then received approximately five 
eyeworm larvae per eye. One was examined 
after 10 days and larvae were seen in both 
eyes. The rat was necropsied and the worms 
were removed. They had molted to the fourth 
stage and the reproductive organs were de- 
veloping normally. The second rat was killed 
25 days after the larvae were placed in its 
eyes. Adult male and female worms were re- 
covered from both eyes. 
LIFE HISTORY OF THE PARASITE 
Apparently little effort had been made be- 
fore about 1927 to ascertain the life cycle of 
Oxyspirura mansoni. Previously Emmerez and 
Megnin (1901), and Emmerez (1918), Ran- 
som (1904), and Ozoux(1910) had attempted 
to transmit the infection directly from one 
chicken to another with embryonated eggs 
and/or first-stage larvae; but they carried the 
work no further when their efforts were un- 
successful. 
Kobayashi (1927) in Formosa and Sanders 
(1928) in Florida found that an intermediate 
host, which they identified as the cockroach 
Pycnoscelus surinamensis Linn., was essential for 
the completion of the life cycle of the para- 
site. Previously Fielding (1926) had shown 
the same roach to be the intermediate host of 
the Australian eyeworm of poultry, Oxy- 
spirura parvovum Sweet. Fielding (1927 and 
1928^) studied the developmental anatomy of 
the Australian eyeworm, but because of his 
uncertainty as to whether the species was 0. 
mansoni or 0. parvovum., he referred to it 
simply as the eyeworm of poultry in his latter 
paper. The validity of 0. parvovum as a species 
was questioned by Tryon (1926). This lack 
of clarity as to species, together with the fact 
that Fielding’s drawings were not identifiable 
with the material found in Hawaii, led me to 
investigate the life history of Manson ’s eye- 
worm under Hawaiian conditions. 
Life cycle in general 
The eggs of the parasite are laid by the 
