584 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



Very large Caprimulgi with toes normal (the outer toe consisting of 

 five phalanges, the hallux of three phalanges), tarsus much shorter 

 than hallux, outer toe as long as middle toe, middle claw not pecti- 

 nated, metasternum deeply 4-notched, powder-down patches present 

 on breast and sides of body, and maxillary tomium with a prominent 

 "tooth" or angular projection at commencement of the strongly 

 convex and very prominent rictal portion. 



The Nyctibiid^e differ from the Caprimulgidse in many of their 

 habits, among which may be mentioned their position while perching, 

 which is upright, the bill pointing upward, in which respect they 

 agree with the Podargidae. So far as known, all Caprimulgidaa lie 

 flat to the perch (or ground) in a horizontal position, when at rest. 



This family is confined to the tropical parts of America, and 

 includes a single genus, Nyctibius Vieillot. 



Genus NYCTIBIUS Vieillot. 



Nyctibiusa Vieillot, Analyse, 1816, 38; Nouv. Diet. d'Hist. Nat., xvi, 1817, 6. 

 (Type, Grand Engoulevent de Cayenne Buiion= Caprimulgus grandis Gmelin.) 



Nictibius (emendation?) D'Orbigny and Lafresnaye, Mag. de Zool., 1839 (Syn- 

 opsis Avium, p. 67). 



Nyctornis ^ (not Nyctiornis Swainson, 1831) Nitzsch, Obs. Av. Art. Carot. Comm., 

 1829,15. (Type, Caprimulgus grandis Gvaelm .) 



(?) Ibijus Rafinesque, Analyse de la Nature, 1815, G9 (nomen nudum). 



In addition to the characters given above under the heading of 

 Family Nyctibiidse the following are diagnostic of the genus Nycti- 

 hius: 



Bill relatively very smaU, broadly angular and much depressed 

 basally, narrow, compressed, and strongly decurved terminally, the 

 basal half (more or less) hidden by the dense, antrorse, laterally closely 

 appressed loral feathering; culmen rounded, strongly defined laterally 

 by a broad sulcus running from nasal fossae to behind base of mcinate 

 tip of maxilla; nostril narrowly ovate (the posterior end narrower 

 and more or less acute), longitudinal, opening against lateral base of 

 the rhinotheca, the membraneous integument of the nasal fossa not 

 inflated; maxillary tomium nearly straight from base of maxillary 

 unguis to a conspicuous angular or knot-like prominence or tooth, 

 thence strongly deflected and more or less convex to the rictus beneath 

 posterior angle, or at least posterior to middle, of eye; mandible 

 abruptly and strongly decurved subterminally, the tip slightly 

 recurved, or straight and inclined downward at a less angle than 

 trend of the subterminal portion; gonys exceedingly short (scarcely 

 longer than nostril), straight, flattened or very broadly and slightly 



a vuKTc^iog, noctu victum quserens. (Vieillot.) 

 b Nu$ (voKzdc), night; bpvic, bird. (Richmond.) 



