I subsequently found a nest; it was about seven inches deep, composed entirely of lichens gathered from the boles of trees, ingeniously woven together and suspended from the small twigs and leaves at the extremity of a branch. There were no eggs in it, but the birds fluttered in great trouble about me, and, what greatly surprised me, uttered a variety of _singing_ notes, unlike their usual song, but many of them closely resembling the notes of other songsters, which made me think that this _Icterus_ possesses the mimicking faculty to some extent. This, however, is a question it would be difficult to decide. It seems certain, however, that this species is incapable of expressing any distressing feeling, such as pain, fear, or parental anxiety, with loud harsh notes like other birds. It is much to be regretted that Azara, who found this species common in Paraguay, did not pay more attention to its habits and language, which make it specially interesting even in a family so rich in strange habits as the _Icteridæ_. 106. APHOBUS CHOPI (Vieill.). (CHOPI BOAT-TAIL.) +Chopi+, _Azara, Apunt._ i. p. 282. +Aphobus chopi+, _Scl. Cat. B._ xi. p. 405. +Psarocolius unicolor+, _Burm. La-Plata Reise_, ii. p. 494 (Mendoza). _Description._--Uniform black, slightly resplendent; bill and feet black; lower mandible sulcated: whole length 9·2 inches, wing 5·2, tail 4·0. _Female_ similar, but smaller and duller; bill not sulcated. _Hab._ S. Brazil, Paraguay, Argentina, Bolivia, and Peru.