(BLACK-HEADED REED-WREN.)
+Donacobius atricapillus+, _Scl. Cat. A. B._ p. 16; _Scl. et Salv.
Nomencl._ p. 5; _Sharpe, Cat. B._ vi. p. 364; _Burm. La-Plata
Reise_, ii. p. 475. +Donacobius brasiliensis+, _d'Orb. Voy.,
Ois._ p. 213 (Corrientes).
_Description._--Above dark chocolate-brown; cap black; wings black,
with a large white patch on the inner primaries; tail black; lateral
rectrices broadly ended with white; beneath ochreous buff; sides of
breast and flanks with cross lines of dusky brown: total length 7·5
inches, wing 2·9, tail 3·7. _Female_ similar.
_Hab._ Guiana, Amazonia, Brazil, Paraguay, and Northern Argentina.
The genus _Donacobius_ contains two species somewhat intermediate between
the Mock-birds and the large Wrens of the genus _Campylorhynchus_. The
well-known Brazilian _D. atricapillus_ extends through Paraguay, where
Azara found it abundant, into Corrientes and the adjoining provinces
of La Plata. It is met with among the reeds on lakes and streams.