128 FALCONID. 
Milvago chimachima, Salv. P. Z. S. 1870, p. 214°; Ridgw. Bull. U. S. Geol. & Geogr. Surv. i. 
p- 468°. 
Ibycter chimachima, Sharpe, Cat. Birds Brit. Mus. 1. p. 39’. 
Supra saturate brunneus, notei plumis vix griseo vel grisescenti-albo marginatis; supracaudalibus medianis 
brunneo et ochraceo late regulariter transfasciatis, lateralibus ochraceis, haud fasciatis; rectricibus ochraceis, 
brunneo 7-transfasciatis et fascia lata brunnea subterminali ornatis; remigibus brunneis, tectricibus 
primariorum grisescenti-albo terminatis ; primariis extus versus basin grisescentibus, brunneo marmoratis, 
intus ochraceo indentatis; pileo cristato et cervice toto ochraceis, fascia angusta supra-auriculari nigra ; 
facie laterali et corpore subtus toto cum subalaribus et axillaribus ochraceis ; tectricibus primariorum 
inferioribus brunneis vel brunneo fasciatis: rostro cyanescenti-albo, ad apicem albo; cera, loris et 
palpebris aurantiaco-flavis ; pedibus plumbeis; iride griseo-brunnea. Long. tota circa 15°5, ale 11:0, 
caude 7°6, culm. 1-05, tarsi 1:95. (Descr. exempl. ex Calobre. Mus. nostr.) 
Juv. Brunneus, pileo et cervice dorso concoloribus et minute ochraceo striolatis; facie laterali brunnea : 
subtus brunneus, plumis omnibus triangulariter ochraceo vel ochrascenti-albo notatis ; pectore et hypo- 
chondriis brunneo et ochraceo transfasciatis; abdomine imo et subcaudalibus ochraceis concoloribus. 
(Descr. exempl. juv. ex Matto Grosso. Mus. nostr.) 
Hab. Panama, Calobre, Chepo (£. Arcé?*), Bay of Panama (Kellett & Wood *®).—Soutu 
America from Colombia to Paraguay’? °. 
This is a common South-American Hawk, and extends northward to Colombia and 
thence to the Isthmus of Panama‘*®. Kellett and Wood procured a specimen many 
years ago in the Bay of Panama, and Arcé sent us examples from Chepo and Calobre ®. 
Naturalists who have travelled in South America state that it has the same habits as 
Polyborus. 
IBYCTER. 
Ibycter, Vieillot, Anal. p. 22 (1816); Sharpe, Cat. Birds Brit. Mus. i. p. 34 (1874); Ridgw. Bull. 
U.S. Geol. & Geogr. Surv. i. p. 469 (1876). . 
Ibycter, as defined by Mr. Ridgway, differs from Polyborus and Milvago in the 
following characters :—*“ Tarsus scarcely longer than the middle toe; outer toe very 
much longer than the inner one, which is but little longer than the posterior toe; 
inner webs of primaries slightly sinuate; nostril circular, situated near the middle of 
the cere, its tubercle either concealed or exposed; anterior outline of the cere doubly 
curved; tarsus without transverse scutelle either in front or behind. Habits strictly 
arboreal.” 
Two species are recognized: J. americanus, which inhabits the greater part of South | 
and Central America, and J. ater, which is confined entirely to the South-American 
Continent. The latter is a small species, with a thicker and somewhat differently 
shaped bill, and a more broadly defined bare eyebrow. 
Mr. Ridgway refers J. ater to a separate subgenus, Daptrius. 
1. Ibycter americanus. 
Aigle d’ Amérique, Buff. Pl. Enl. 417°. 
Red-throated Falcon, Lath. Gen. Syn. i. p. 97°. 
