588 BULLETIN 5 0, UNITED STATES NATIONAL MUSEUM 



Genus MILVAGO Spix 



Milvago Spix, Avium Species Novae (Av. Bras.), i, 1824. (Type, by monotypy, 



M. ochrocephalus Spix = Polyborus chiniachima Vieillot.) 

 Parasifalco Lesson, Compl6ment des Oeuvres de Buffon, vii, 1836, 38 (new name 



for Milvago Spix). 

 Parisifalco (emendation) Kaup, Isis, 1847, 352, 354. 

 Ibycter Reichenow, Die Vogel, i, 1913, 372, part. 



Small Polyborinae (wing about 261-300 mm.) with nostril circular, 

 near middle of cere, its central tubercle exposed; tomial tooth and 

 notch distinctly indicated; head (including malar region) normally 

 feathered; claws sharp and strongly curved, and planta tarsi with two 

 longitudinal series of hexagonal scutella. 



Bill moderate in size, the culmen less than to slightly more than 

 one-third as long as tarsus, its depth at anterior portion of cere (in 

 front of nostril) equal to more than half the length of culmen, the 

 latter gradually decurved from base, the tip of maxilla forming a 

 distinct but not abrupt unguis; maxillary tomial "tooth" and mandib- 

 ular notch rather distinct; cere rather short, with a very oblique, 

 doubly curved anterior outline, the upper and anterior portion 

 distinctly convex, the lower and posterior portion on a line (vertically) 

 with middle or even posterior edge of nostril; nostril small, circular, 

 a little anterior to middle of upper part of cere, its central bony 

 tubercle distinct. Wing long and rather pointed, the longest primaries 

 considerably exceeding longest (proximal) secondaries; second to 

 fifth primaries (from outside) longest, the first (outermost) equal to or 

 shorter than sixth; inner webs of four outer primaries sinuated (less 

 distinctly on fourth); primaries, 10, secondaries, 13. Tail about two- 

 thirds as long as wing, slightly rounded, the rectrices (12) rather 

 narrow, but with broadly rounded tips. Tarsus about one and a 

 half times as long as middle toe without claw, covered with four longi- 

 tudinal rows of very regular hexagonal scutella, the three lower scutella 

 of the anterior inner series twisted to the front and appearing as if a 

 continuation of the transverse scutella on upper surface of toes; 

 outer toe very slightly longer than inner toe; claws moderate in size, 

 moderately curved, and rather sharp.^ 



^ The skeleton of Milvago shows the following characters: Skull most like that 

 of Daptrius americanus, but frontal with a very deep median valley anteriorly and 

 suddenly much inflated posteriorly; nostril more regularly circular and more 

 completely rimmed, its tubercle more exposed. Length of skull, 56.5 mm.; 

 width 29.5; depth, 24.5. The sternum agrees with that of both Daptrius and 

 Polyhorus in possessing a pair of very deep single notches. It measures 43 mm. in 

 length by 29 in greatest width. Tibia 67.5, tarsus 57 mm. The syrinx of Milvago 

 is said to be similar to that of Polyhorus except that the intrinsic muscles reach just 

 beyond the first bronchial semiring. 



