Oxyspirura mansoni — SCHWABE 
27 
debris by the tip of the tail. Embryonated 
eggs were found in the midgut until the 
seventh day, and numerous larvae were pres- 
ent until the ninth day. A single larva was 
found in the midgut on the eighteenth day. 
It was almost double the size of those seen 
there previously. 
First-stage larvae were observed for the 
first time in the body cavity on the eighth 
day, and by the tenth day many were seen. 
Some were wandering freely in the cavity, but 
most were found in the adipose tissue lining 
the abdominal wall. Apparently they mi- 
grated through the wall of the midgut, and 
after wandering in the body cavity for a short 
time, burrowed into the abdominal fat. The 
larvae became lethargic at this stage and were 
extremely difficult to extricate. They grew 
only slightly in length, broadened consider- 
ably, lost their long, pointed tails, and as- 
sumed a more-or-less club-shaped appearance 
because of the enlargement of the several 
large rectal cells. 
Incomplete encystment actually occurred in 
this stage in some instances, with the ill- 
defined cyst measuring approximately 0.3 
mm. by 0.5 mm. Thereafter little change took 
place until about the seventeenth day when 
larvae measuring 250^^ to 320)U in length and 
with the cuticular sheath loosened at both 
the anterior and posterior ends were observed. 
Larvae in this pre-molting condition were 
seen until the twenty-fifth day, at which time 
a second-stage larva which measured 990)U 
in length was observed. 
Complete encystment occurred in the se- 
cond stage of larval development. The cysts 
were nearly spherical in shape and measured 
approximately 0.8 mm. by 0.8 mm. They 
were found attached to the alimentary tract, 
particularly around the rectum and entangled 
in the Malpighian tubules. The cysts were 
thin-walled an-d transparent. The wall, ap- 
parently of loose connective tissue, consisted 
of a gelatinous matrix and a few scattered 
cells. The wall was richly tracheated, which 
constituted evidence that the cyst was formed 
by the cockroach and not secreted by the 
parasite. The cysts were filled with fluid and 
the coiled larvae were able to move about 
freely in them. 
On the thirty-third day encysted second- 
stage larvae measuring 1.8 mm. to 1.85 mm. 
were observed; those on the fortieth day had 
attained a length of 2.6 mm. to 4.5 mm. On 
the forty-fifth day a second-stage larva 6.62 
mm. in length was observed in the process of 
molting. Ecdysis evidently takes place be- 
tween the forty-fifth and fiftieth days, at 
which time the last molting larvae were seen. 
Many of the parasites were able to free 
themselves from their cysts through their in- 
creased activity during the period of ecdysis, 
and on the fifty-first day numerous third- 
stage larvae were found, some encysted, but 
most wandering freely in the body cavity. 
These early third-stage larvae measured from 
7.4 mm. to 8.3 mm. in length and were ex- 
tremely active. 
Whether or not those larvae which were 
unable to free themselves during the molting 
period eventually escape from the cyst could 
not be ascertained. 
Upon the attainment of the third stage, the 
larvae were infective to the definitive host, as 
was shown by their appearance in the eyes of 
chickens within 5 minutes after they were in- 
troduced into the mouth by pipette. 
Development in the definitive host 
Large numbers of infective larvae were ob- 
tained from roaches by use of the Baermann 
apparatus. They were introduced by pipette 
into the mouths of 4- week-old chicks. The 
larvae migrated up the naso-lacrimal ducts 
and were observed to enter the eyes several 
minutes after they were introduced. Chicks 
were killed every 2 days, and the worms were 
removed from the eyes and examined micro- 
scopically. 
On the second day the larvae appeared 
much the same as they did in the cockroach. 
On the fourth day several third-stage larvae 
in the process of molting were observed. 
