As night approached I expected that it would become animated; but it did not stir, nor shew any sign of vivacity, though I watched it till it was quite dark. Several times in the evening I went into the room, up to ten o’clock, but it was where I had left it. About three in the morning I had occasion to go in again with a candle; the Potoo had not altered his position, and when the day came, there he was unmoved, nor do I believe he had stirred during the whole night. Thus he remained during the next day; I put his beak into water, and let fall drops upon it, but he refused to drink: I then caught beetles (_Tenebrionidæ_) and cockroaches, but he took no notice of them; and though I repeatedly opened his beak and put the insects into his broad and slimy mouth, they were instantly jerked out by an impatient toss of his head. Towards this evening, however, he began to glower about, and once or twice suddenly flew out into the midst of the room, and then fluttered either to the ground, or to some resting place. Many little _Tineæ_ were flitting around my dried bird-skins, and I conjectured that he might be capturing these, especially as when at rest his eye would now and then seem to catch sight of some object, and glance quickly along, as if following its course. The statement of Cuvier, that “the proportions of the Nyctibius completely disqualify it from rising from a level surface,” I saw disproved; for notwithstanding the shortness of the tarsi, (and it is, indeed, extreme,) my bird repeatedly alighted on, and rose from, the floor, without effort. When resting on the floor, the wings were usually spread; when perching, they about reached the tip of the tail. If I may judge of the habits of the Potoo from what little I have observed of it when at liberty, and from the manners of my captive specimen, I presume that, notwithstanding the powerful wings, it flies but little; but that sitting on some post of observation, it watches there till some crepuscular beetle wings by, on which it sallies out, and having captured it with its cavernous and viscid mouth, returns immediately to its station. Mr. Swainson appears to consider that the stiff bristles, with which many _Caprimulgidæ_ are armed, have a manifest relation to the size and power of their prey, beetles and large moths, while these appendages are not needed in the swallows, their prey consisting of “little soft insects.” (Class. Birds.) But here is a species, whose prey is the hardest and most rigid beetles, of large size, and often set with formidable horns,—which has no true rictal bristles at all!