Mydæa anomala Jaenn., 
a parasite of South-American birds. 
By 
Dr. J. C. Nielsen. 
;B 
In 2 collection of various zoological objects, which the Zoolo- 
gical Museum in Copenhagen received in 1910 from Mr. I. Mo- 
gensen, åa Dane now established in Concepcion, Argentina, there 
was a finch, Spermophila gutturalis, bearing on the belly near the 
anus a great tumor, the top of which was open, showing a dipte- 
rous maggot; the bird was shot on the nest, which contained 
two eggs. ; 
In addition to this bird the collection also comprised several 
maggots squeezed out from tumors on nestlings of Agelaus thilius, 
a puparium and a fly bred from such maggots. 
On my demand Mr. Mogensen collected in the following 
months, December 1910 — January 1911, more material. He 
succeded in finding tumors on nestlings of Homorus lophotes and 
Pitangus sulfuratus bolivianus and he observed in the nest of a 
thrush, Mimus modulator, two nestlings, which were both strongly 
infested with maggots (Fig. 2), and such were also found in the 
vicinity of the anus of the female bird. He also reared the fly, 
which proved to belong to the species: Mydæa anomala Jaenn!). 
U F. Jaennicke: Neue exotische Dipteren (Abhandl. herausgeg. v. d. 
Senckenbergischen naturf. Gesellschaft VI, 1866—67 pag. 377). Me- 
sembrina anomala. 
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