Genus — F A L C O . 
Falco Linne, Syst. Nat., 10th Ed., p. 88, 1758 . . Type F. suhbuteo. 
Hypotriorchis Boie, Isis 1826, col. 976 . . Type F. suhbuteo. 
Dendrofalco Gray, List Genera Birds, p. 3, 1840 . . Type F. subbuteo. 
Small Falconine birds with hooked toothed bills, long wings, long tails and 
short legs and feet. 
The bill is short, sharply hooked, with a distinct notch or tooth on the 
edges of the upper mandible, while the under mandible is shallow with blunt 
squarish end and notches along the edges. The cere is comparatively small, 
while the nostrils are circular with a central bony obstruction. 
The wings are very long and pointed, with the second primary longest, 
but the first almost as long and equalling the third, the rest rapidly decreasing. 
The tail is long, slightly rounded, and is just over half the length of the 
wings. 
The legs are short ; the tarsal-covering consists of reticulate scales, much 
smaller, almost minute, on the hinder aspect of the tarsus. 
The toes are stoutish and long, the middle toe exceeding the tarsus in 
length. 
The Australian bird here assigned to Falco agrees very closely with the 
type of the genus, and as that name has been very loosely applied, I herewith 
give a few remarks on the views of the genus held by various workers. 
Kaup, in the Gontrib. Ornith. (Jardine) 1850, p. 51, in his subfamily 
Falconinse, ranged five genera, viz. : Hierax, Tinnunculus^ Harpagus, Falco and 
leracidea. The first, third, and fifth he could not subdivide, but the second 
and fourth provided each a full complement of subgenera, viz., PoUhierax, 
Erythropus, Poecilornis, Tichornis and Tinnunculus as subgenera of Tinnun- 
culus, and Msalon, Hypotriorchis, Gennaia, Falco and Hierofalco as subgenera 
of Falco. 
Sharpe, in the Cat. Birds Brit. Mus., Vol. I., 1874, only admitted three 
genera, with no subgenera, for these two genera, viz., Cerchneis, Falco and 
Hierofalco. 
Gurney commented on this proposition as follows {Ibis 1881, p. 277) : 
“I propose now to consider the cluster of species which Mr. Sharpe has 
associated under the generic title of Cerchneis, and which appears to me to 
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