Naturalists have said a great deal about the well-known Silver-bill (the most important member of my "_Spectacular_" group), the question as to whether the black and red birds are sexes or two distinct species having long remained unsettled. Azara, writing in the last century, under the heading _Pico de Plata_, rightly described the red bird as the female of the black; but, unfortunately, in another part of his work he described the female again as a different species, naming it _Suiriri chorreado_. Darwin also separated the sexes, and gave the name of _Lichenops erythropterus_ to the red-plumaged bird. The following extract gives only a portion of his argument, and is interesting to read, even now, when the question has been finally set at rest, as it shows how much the two birds differ:--"The tail of _L. erythropterus_ is squarer and contains only ten feathers instead of twelve: the wing is 4/10 of an inch shorter; and the secondaries relative to the primaries are also shorter. The red colour on the primaries represents but does not correspond with the white on the black feathers of _L. perspicillatus_; and the secondaries in the two birds are quite differently marked. In _L. erythropterus_ the third, fourth, and fifth primaries are the longest, and are equal to each other; the second is only a little shorter than the third. In _L. perspicillatus_ the third is rather shorter than the fourth and fifth; and the second is proportionately shorter relative to the third, so that the outer part of the wing in this species is more pointed than in _L. erythropterus_. The outer claw in the latter species is only in a small degree straighter than in the former; and this, considering that _L. perspicillatus_ is generally perched, and when on the ground can only hop, and that _L. erythropterus_ feeds there entirely, and walks, is very remarkable." When one considers the habits of the two birds, even where they are most abundant and seen continually, it is indeed difficult to believe that they are of the same species. They are never seen associating together, even in the love-season, and when I have watched a pair actually engaged in constructing their nest, they appeared to keep as far apart as possible. More than that, the male, while unfriendly towards all other species, appears to cherish a special antipathy against the red bird; and when one comes near him never fails to pursue it with the greatest virulence from the neighbourhood. He is also strictly solitary, but the red birds frequently unite in small parties, especially in autumn, when I have often seen as many as a dozen together.