196 
From the observations of Mr. Mogensen it appears that the 
maggots attack both nestlings and elder birds. The fly seems not 
to be rare and to cause severe damage among the birds. The in- 
fested nestlings are killed by the maggots, which leave the tumors 
after the death of the bird and pupate in the ground. Already 
5—6 days after the pupa- 
tion the flies emerge. I do 
not know, whether the pre- 
sense of the maggots also 
causes the death of the elder 
birds ; the above mentio- 
ned Spermophila gutturalis 
appeared to be in good health. 
Yet it may be that the pre- 
sense of more maggots in a 
bird will prove fatal to it. 
Fig. 1 represents the 
above mentioned Spermophila 
gutturalis ; the plumes have 
been removed in front and 
from the sides of the tumor, 
but the tumor itself was quite 
bare. The length and breadtk 
are almost equal, measuring 
about 9 mm, and the diame¬ 
ter of its opening ca. 7 mm; 
the tumor contained two larvæ, 
which were almost fullgrown. While this bird was infested 
with these two maggots only, the nestlings of Mimus modu- 
lator were much more infested. The length of the nestlings 
was ca. 9 cm and on both were found more than a score of mag¬ 
gots, measuring from IV 2 —1 5 mm Fig. 2. 
The larvæ were situated on all parts of the nestlings, also 
on the head, the wings and the legs. 
Fig. 1. Spermophila gutturalis. 
R. H. Stamm phot. 
