Australian Birds in the Collection of the Linnean Society. 953 
afford some assistance towards the subdivision of the family. In 
it the bill, like that of the group to which we would restrict the 
name of. Muscipeta, is intermediate in breadth between the bills 
of the true Muscicapa and Platyrhynchus. It is at the same time 
moderately short; in which it differs from the bill of Muscipeta. 
The tail is even, by which character it may be also distinguished 
from the latter genus; and moderate in length, by which it is 
separated from the equally even but long-tailed Seisura. In 
drawing a line between the species of this family we are inclined 
to lay much stress upon the structure of the tail. Nearly allied 
as the whole group is to the Fissirostral Birds which feed upon 
the wing, and being themselves accustomed to seize their prey 
in the air, a member which, like the tail, contributes to their 
powers of flight, or support upon the wing, must be considered 
as of much importance: and in a numerous family like that 
before us, which calls for subdivision, and in which no stronger 
mark of distinction is tangible, it appears to us that the variations 
in the structure of the tail afford not merely a convenient arti- 
ficial ground of separation, but one which is sufficiently natural. 
The group, as we have at present characterized it, does not 
appear to be peculiar to New Holland. Some American spe- 
cies, such as the Muscicapa querula and M. rapax of Wilson's 
** Ornithology," appear to belong to it. | 
1. RuBECOoLOoriDEs. My. plumbeo-grisea, gutture pectoreque 
rufis, abdomine albido, pteromatibus ONE rectricibusque 
fuscis. 
Pteromata remigesque interiores pallido fascoanargitiate. Tec- 
trices inferiores albidæ, fusco-variegate. Remiges rectri- 
cesque subtus grisescentes. Rostrum nigrum. Pedes fusci. 
Lon glue corporis, 51; alë a carpo ad remigem quartam, 3; 
cauda, 23 ; rostri ad frontem, 2, ad rictum, 4 ; tarsi, 4. 
2. PLUMBEA. 
