Oxyspkuramansoni — Schwabe 25 
definitive host. They gain entrance when the 
host roach is consumed by a suitable bird. 
The larvae seldom pass farther than the crop 
of the definitive host (Fielding, 1926), where 
they migrate from the tissues of the roach 
under stimulation of heat and moisture. 
The infective larvae then crawl up the eso- 
phagus, reach the roof of the mouth, and 
gain entrance to the eyes through the naso- 
lacrimal ducts. During this study worms have 
been observed in the eyes of a chicken within 
5 minutes after the ingestion of an infected 
roach. 
The eyeworm eggs 
During the course of this study several at- 
tempts were made to recover embryonated 
eggs from the eyes of infected birds. Fluid 
was removed from the eye with a pipette and 
examined beneath the microscope, but in no 
case were eggs observed. However, they were 
recovered in varying quantities from the crop, 
intestinal contents, and feces of infected 
birds. The eggs were elliptical in shape, had a 
shell thickness of 1 to 1.5 a-^d were approxi- 
mately the same size as those measured in the 
TABLE 4 
Reported Measurements of Eyeworm Eggs (All Measurements in Microns) 
SCHWABE 
RANSOM 
SWEET 
FIELDING 
FIELDING 
STAGE 
RANGE 
(Oahu, T.H.) 
(Florida) 
(Australia) 
(Australia) 
(Australia) 
1948-49 
1904 
- 1910 * 
1928t 
1928* 
Embryonated eggs 
Max. 
60x45 
from feces 
Min. 
42x23 
Ave. 
53x40 
Embryonated eggs from 
Max. 
50x28.5 
65x45 
45x30 
vagina and uteri 
Min. 
35.7x17.8 
50x40 
33x25 
Ave. 
41.6x23.7 
43x31 
41x30 
Shelled, segmented eggs 
Max. 
42.9x32 
from uteri 
Min. 
28.4x14.3 
Ave. 
36.7x22.9 
Unshelled, non-segmented 
Max. 
28.25x10.7 
28x14 
eggs from uteri 
Min. 
21.6x7.2 
24x12 
Ave. 
23.4x9.5 
24x12 
Fig. 6. Photomicrograph of the vagina of a gravid 
female eyeworm showing embryonated eggs. 
adult females in the eyes of the definitive host. 
They are washed down the naso-lacrimal 
ducts with the eye fluid into the mouth, 
swallowed, and finally passed out with the 
excrement. The intermediate host is infected 
by eating embryonated eggs or first-stage lar- 
vae in the feces of infected birds. After a de- 
velopmental period of approximately 51 days 
in the roach, the larvae are infective to the 
*0. parvovum, 
fold fixed 0. mansoni eggs. 
