36 
There are certainly two different species, possibly 
families, of worms concerned — a shorter, about an inch 
long and easily dissected out, and a larger about four 
inches long and inextricably coiled. In some instances 
microfilaria have been definitely absent from the blood 
and in others present. 
An analysis of the duration of the birds residence in 
the garden did not yield any pertinent information. 
Some of the birds had been here up to eight years and 
one only twenty days. All that we can derive from this 
is that some at least of the cases are importations. 
Whereas this problem is most fascinating biologically, 
I feel, as I did last year, that at present it is not an 
economic one, and to be dealt with slowly — feeling our 
way, and not by more or less heroic, heavy-handed 
clinical methods. 
Avian Spiropteriasis. In the past years this pest was 
considered under the heading of "Spiroptera incerta." 
This year I encountered a case where the female worm 
was different (microscopically) and therefore of a dif- 
ferent species. This suggests that several species may 
be able to produce this avian infestation and since the 
hygiene is the same, we must group them under one head 
until final study settles all the varieties. 
The effect of finding multiple species of spiroptera 
will be to complicate certain phases of our investigative 
work; in order to trace the course of an infestment it 
will be necessary to identify each infestment microsco- 
pically as to species. The appearance of the ova is the 
same, however, in the several species, and this leaves 
the detection phase unchanged. 
The birds affected this year represent several new 
hosts. They were: Sun Bittern, Blue-crowned Conure, 
Mexican Crested Hangnest, Canary, Red wattled Plover, 
American Bittern, Chestnut-eared Finch. All of these 
came from the bird house, except the Conure and 
American Bittern. The two exceptions came from the 
Parrot House. The cage distribution in the bird house 
is not significant of any especially infected cages. 
