41 
Observations on Spiroptera Incerta in the Parrots. 
Dr. F. D. Weidman. 
The appended table shows a high mortality for the 
past year. 
Summary. 
Deaths Among PSITTACI. 
Year Ending. 
Vermin- 
ous. 
Not 
vermin- 
ous. 
Total 
from 
all 
causes. 
Per 
cent, 
dying 
with 
worms. 
Total number 
of psittaci 
in collection. 
March 1, 1906 
3 
45 
48 
6 
Not obtainable. 
March 1, 1907 
16 
29 
45 
36 
Not obtainable. 
March 1, 1908 
17 
36 
53 
32 
Not obtainable. 
March 1, 1909 
20 
16 
36 
56 
Not obtainable. 
March 1, 1910 
10 
30 
40 
25 
Not obtainable. 
March 1, 1911 
12 
29 
41 
29 
132. 
March 1, 1912 
24 
57 
81 
30 
139. 
Total 
102 
242 
344 
30 
The proventricular worms noted in years past were 
collected and investigated. Recalling the frequency of 
commensalism in lower animals the first point to be 
determined is whether these worms cause death. The 
charts herewith would indicate at first sight that the 
verminous cases appeared only incidentally and did not 
cause death. Table B shows that the average of vermin- 
ous birds for seven years has been 30 per cent. In only 
one year, 1909, has this average been departed from to a 
marked degree. We can exclude 1906 because the cases 
were for the first time appearing. A chart which has been 
prepared would indicate the same, where there is a 
close correspondence between the verminous and non- 
verminous curves especially during the past year where 
we have had a greater number of cases to record. 
