There is in the collection of the Philadelphia Academy, a specimen from Mexico, and another from California, differing in shade of color only from the _Antrostomus vociferus_, and from which the distinctive characters are too slight to establish a separate species. We regard these specimens as _C. macromystax_. The length of the bristles in Wagler’s description applies as well to _A. vociferus_, and we think it probable that his name is a synonyme. The following is a translation of Wagler’s description or notice as above cited, and is at the end of an elaborate and valuable paper, in which he describes several new American species of birds:— “At the conclusion of these descriptions of birds, I will yet remark that we have received from Mexico, also, a Caprimulgus (which specimen unfortunately is without the tail), that nearly resembles ours in size and color, but which nevertheless may be distinguished at a glance; the tarsi on their upper sides are hardly feathered to the middle, and the bristles on both sides of the upper mandible are uncommonly stiff, and longer than in any other American Night Swallow, nearly as long as the head without the bill, and are turned _rake-like_ obliquely downwards. I have named it, therefore, _Caprimulgus macromystax_. The feet are short, as in ours; also as in ours, the claw of the middle toe on its inner border is pectinated, the primaries are small, the second, third, and fourth, externally from their middles to their ends, are strongly sinuated; they are brown-black, without white spots, but have internally and externally rust-red angular dots.” 2. Caprimulgus minor. Forster. Catalogue of the Animals of North America, p. 13. London, 1771. A name given without being accompanied by a description, though probably applicable to _Antrostomus vociferus_, which was known to some of the older naturalists, and, previous to the introduction of the binomial nomenclature, was called _minor_, in distinction from the _Caprimulgus europæus_. The catalogue by Forster above referred to is a pamphlet, and is, so far as We know, the first attempt at an enumeration of the species of all classes of animals inhabiting North America. There is also a catalogue of the Plants of North America by the same author. 3. Antrostomus californianus. Bonaparte, Cons. Av. p. 61. (1849.) The description by the Prince of Canino, as above, is as follows:— “(Confer Capr. nuttalli, Aud. Am. Orn., 2d edit., t. 495,) ex California, Vix Turdi magnitudine. Mas. Griseus, nucha fulvescenti, abdomine cervino, nigro undulato; gula macula utrinque alba nigro terminata: remigibus fuscis, macula mediana alba, rectricibus lateralibus nigricantibus, extima late ad apicem candida.” The characters here given differ so essentially from those of any other species of _Antrostomus_, that we much suspect that the bird alluded to neither belongs to this genus, nor is an American species. 4. Caprimulgus europæus. Linn.