CHOCOLATE TYRANT 135 
Noseda as a naturalist, if we did not remember that 
Gilbert White at the same period was trying to 
prove the hibernation of Swallows in England. The 
whole of the discussion appears in the Birds of 
Paraguay, under the description of the Chopi; and 
Noseda is there allowed to state his own case; after 
which the better observer, Azara, gives five ob- 
jections to the theory, any one of which would be 
sufficient to demolish it. 
CHOCOLATE TYRANT 
Myiotheretes rufiventris 
Above and below smoky grey, clearer on the head and breast ; 
belly, crissum, and under wing-coverts bright rufous; wings black, 
inner secondaries bright chestnut terminated with white, outer 
secondaries black, tipped with white; wing-coverts grey, margined 
with white; tail black, outer margins of external pair of rectrices 
and tips of all whitish; two outer primaries emarginated ; bill and 
feet black; length 9.5 inches. Female similar, but outer primaries 
not emarginated. 
Tue Tyrant Birds (Tyrannidz) are a family of in- 
sectivorous birds peculiar to America. They are the 
Flycatchers of the New World, and in very many 
of the smaller species are curiously like the Old 
World Flycatchers in appearance and habits. But 
structurally they are not nearly related to them. 
They belong to the sub-order Olygomyodz, the 
Passerine birds which are (or ought to be) songless. 
