I0O SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
tion of the eyeworm because their feces are too scattered to be eaten 
to any great extent by vector cockroaches (Schwabe, 1951). 
Experimental definitive hosts—In Florida the following wild birds 
were experimentally infected: Blackbird (Agelaius phoeniceus phoe- 
niceus), bobolink (Dolichonyx oryzivorus), loggerhead  shrike 
(Lanius Iudovicianus Iudovicianus), Florida jay (Aphelecoma 
cyanea), and the pigeon (Sanders, 1928, 1929). 
The eyeworms will develop to maturity in the eyes of guinea pigs 
(Fielding, 1927) and white rats (Schwabe, 1951) ; but when placed 
in the mouths of these rodents, the larvae were unable to reach the 
eyes. 
Development in the definitive host—Host birds eat the cockroach 
containing infective third-stage larvae. The larvae (pl. 6) leave the 
cockroach host in the bird’s crop and migrate up the esophagus to the 
roof of the mouth, then through the nasolacrimal ducts into the eyes. 
Infestation of the eyes of chickens has been produced within 20 
minutes after they had eaten infected cockroaches (Sanders, 1928, 
1929). Larvae placed in the mouths of 4-week-old chicks were ob- 
served to enter the eyes several minutes later (Schwabe, 1951). The 
worms molt within a few days to fourth-stage larvae, and after about 
3 weeks they molt into adult worms. The sexually mature worms are 
found beneath the nictitating membranes, in the conjunctival sacs, and 
nasolacrimal ducts of the bird. The adult females begin to lay eggs 
in the host’s eyes about 11 days after becoming mature. The eggs are 
washed down the nasolacrimal ducts with the eye fluid into the mouth, 
swallowed, and passed out with the feces. (Schwabe, 1951.) 
Illingworth (1931) found as many as 205 worms in the eyes of a 
single chick, and Schwabe (1950a) states that the approximate maxi- 
mum number of worms found in the eyes of a single bird is 200. 
Effect of worm on definitive host—In heavy infestations (60 
worms per eye), the eye shows signs of irritation ; there is continuous 
winking and the bird rubs its head on its wing feathers. Other symp- 
toms include lacrimation, nasal discharge, white corneal opacity, and 
inflammation of the nictitating membrane. The bird may scratch its 
eye with its foot, lacerating the outer surface of the eyelids, and finally 
become blind. Less marked disturbances occur in mild infestations. 
(Sanders, 1929.) 
Blindness and advanced pathologic changes found in the eyes of 
heavily infected birds are possibly the result of secondary viral or 
bacterial infections which may be further complicated by the death 
and decomposition of the worms in the eyes (Schwabe, 19502). 
Distribution —China, Mauritius, Brazil, Hawaii, Jamaica, Florida 
