BIRDS OF NORTH AND MIDDLE AMERICA 549 



Large-headed, stoutly built Falcones without tomial tooth or notch; 

 relatively large cu'cular bony-rimmed nostril without central tubercle; 

 tarsus and greater part of toes uniformly covered with small, rough, 

 imbricated scales; hallux nearly as long as lateral toes; and with a 

 conspicuous bushy erectile decumbent crest of lanceolate rigid-shafted 

 feathers covering entire pileum. 



General aspect of skull stongly falconine, but superofrontal width 

 relatively much greater than in Falconinae and Polyborinae and pala- 

 tine sm-face correspondingly narrow; interorbital width of frontal equal 

 to more than half the length of skull from base of maxillary; super- 

 ciliary process of lachrymal greatly developed, extending nearly across 

 orbit, its width equal to more than one-third its length; width of con- 

 jomed palatines equal to less than twice the width of superciliary 

 process of lachrymal and less than half theu- own length; maxillary 

 tomium without trace of tooth; mandible very broad and strong; 

 the rami with a large longitudmally oblong-ovate, posteriorly acute 

 vacuity, the tomium without trace of subterminal notch. Nostril 

 relatively larger than in Falconinae and Polyborinae, cu-cular or ver- 

 tically broadly oval, its bony rim much elevated on posterior side, 

 without obvious central tubercle. Sternum with greatest width 

 equal to about two-thkds its length, its posterior margm truncate 

 or faintly concave, entire, without trace of notches or foramina; 

 carina sterni about equal in length to scapula, much longer than cora- 

 coids or fmxula; spina externa very broad and deep.^^ 



Larynx with intrinsic muscles attached to first bronchial semiring 

 only. 



Pterylosis (according to Nitzsch) as in Falconinae, but with dorsal 

 stem of spinal pteryla enlarged on all sides, undivided, and sparsely 

 feathered to the caudal pit, thence diminished and continued as a 

 narrow band along the caudal vertebrae to the oil gland; lumbar tract 

 distinct but short and separated from the crm-al tracts ; inferior tract 

 narrow in all its parts, the inner branch indistinct at end of gular 

 portion, the outer branch completely separated from the pectoral 

 stem, somewhat broader than the main stem itself, and distinct 

 from it; ventral portion of main stem removed far outward, running 

 along the margin, and terminating laterally in front of the anus. 



This subfamily is peculiar to continental Tropical America and 

 contains, so far as Imown, a single monotypic genus, Herpetotheres. 



From its external appearance this remarkable form conveys little 

 suspicion of its near relationship to the falcons. The plumage has 

 the softness or laxity of that of the more weakly organized buteonine 

 forms, as Harpagus and certain genera of Perninae, while the scutella- 



^^ Only the skull, and sternum, with attached scapulars, coracoids, and furcula, 

 of this remarkable form have been examined. 



