SYSTEMATICALLY ARRANGED BY DR. T. T. KAUP. 
a. Subgenus Herpetotheres, Vieill.— The compressed bill curved 
like Falco ; ear with a distinct facial disk like Circus. S. America. 
The Falconine type. 
1. Circaétus cachinnans, Kp.; F. cachinnans, Linn., Spix, t. 3, 
ad., Azara, 15; Herpetoth. cachinnans, Vieill.—The head-feathers 
elongated ; tarsus 55-57 mm. long, 
2. O. brachypterus, Kp.; F. brachypterus, Temm. pl. col. 141, 
116; Sparv. semitorquatus et leucomelas, Vicill., Azara, N. 28, 
29.—White necked Falcon, Lath. Longer than cachinnans ; tarsus 
81-85 mm. long. 
3. C. xanthothorax, Kp.; F. wanthothoram (ad.) et leucauchen 
(young), Temm. pl. col. 92, 306.— Tail with 4 white bands ; tar- 
sus 55-60 mm. long. 
4. CO. concentricus, Kp.; I. concentricus, Ill.— Large like a 
female JV. fringillarius ; beneath with a great number of bars, and 
2-3 white tail-bands. 
b. Subgenus Gymnogenys, Less. — Head very small; wings very 
long; tarsus slender like a Circus; the face naked. The Miluine 
type. 
5. C. radiatus, Kp.; Vuliur radiatus, Scop.; F. madagascar- 
iensis, Lath., Gmel.; Z’. gymnogenys, Temm. pl. col. 307.— Tarsus 
89; middle toe 40; external toe 25; internal 29 mm. long. Dr. 
Smith thinks that the Polyboroides typus of the Cape is very dif- 
ferent from the radiatus of Madagascar. I haye no opportunity 
to compare them. 
ec. Subgenus Spilornis, G. Gray.— The wings extend to the 
middle of the long tail; middle toe twice shorter than the tarsus, 
the claws edged. The Accipitrine type. 
6. Circaétus cheela, Kp.; F. cheela, Lath.; F. bacha, Daud., 
Vaill. 15; albidus, Cuy.; pl. col. 19; bido, Horsf.— Breast and 
crop ash-brown without spots and bands; lower breast, belly, tibial 
feathers and under tail-covers, with 3-4 pairs of white round spots. 
Afgica and Asia. 
7. C. holospilus, Kp.; Buteo holospilus, Vig. — Beneath with a 
great number of white spots; black bordered, without black bars. 
Asia. 
8. C. undulatus, Kp.; Heematornis undulatus, Vig.; Cire. 
nepalensis, Hodgs.— Beneath with numerous black bars and small 
white spots. 
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