140 PROCEEDINGS OF THE ACADEMY OF 



2. Second quill longest, but difference between first and second less than 

 half that between second and third. Outer web of first and second 

 sinuated : inner web of first emarginated ; of none, sinuated. 



aurantius,* rufigularis.f 

 b. Middle toe shorter than tarsus, the latter closely feathered on upper por- 

 tion ; first quill shorter than third. 



3. (Subgenus Hierofalco, Cuvier.) Outer webs of second, third and fourth 

 quills sinuated (the last only perceptibly ;) inner web o ( first eruar- 

 ginated, of second sinuated. More than the upper half of tarsus 

 feathered, the feathering interrupted behind only by a narrow (almost 

 concealed) strip from the knee downward. 



candicans,\ islandicws,\ sacer,\\ labradorus.^ 



4. (Subgenus Gennaia, Kaup.) Outer webs of second and third quills 

 sinuated; inner web of first emarginated, of second sinuated. Only the 

 upper third of the tarsus feathered ; its posterior face and the whole 

 knee bare mexicanus.**' 



B. Front of Tarsus with a double series of transverse scutellae, these alter- 

 nately joining; second and third quills equal and longest or, third 

 lougest ; first and second with inner webs emarginated. Tarsus scarcely 

 feathered below the knee. 



a. (Subgenus llypotriorchis, Boie.) Basal joint of toes with irregular scales. 



5. Third quill lougest; second and third with outer webs sinuated. 



columbarius-ff, richardsonii.W_ 



b. Basal joint of toes with transverse scutellae. 



6. Third quill longest ; second, third and fourth with outer webs sinu- 

 ated ; scutella? of tarsus and toes large and well defined, uninterrupted 

 from knees to claws .femoralis.\\ 



7. (Subgenus Tinnunculus, Vieill.) Second and third quills equal and 

 longest; second and third with outer webs sinuated. 



s/)art>m.s,|||| (with all its varieties) ; sparveroides,^ leucophrt/s.[l) 



B. Nostril not circular, and without bony tubercle. Bill variable in form, but 

 its breadth never equal to its height. t the base; gonys only mode- 

 rately convex. No "tooth "on the commissure, but, in its stead, a more 

 or less prominent " lobe " or " festoon ; " lower mandible neither trun- 

 cated nor notched. Nostril variable iu form, but never circular, and 

 never with a central bony tubercle ; though there is sometimes a carti- 

 laginous projection, to be distinguished by its different appearance and 

 situation. Tarsus, when bare, with a frontal and posterior series of 

 transverse scutellse. 



* Falco aurantius, Gmel., Syst. Nat.. 1789, 283. Falco deirolcucus, Temm., PL Col. 348, 1830. 



f Falco rufigularis, Daud.,Tr. Orn. ii. 131, 1800. (F. aurantius, Temm., PI. Col., and Cassin, 

 B. N. Am.) 



| F. candicans. Gmel., Syst. Nat,, 1789, 275. 1 



\ F. islandicus, Sab., Linn., Trans, xii., 1818, 528. 



|j .F. sueer, Forster, Phil. Trans. Ixii.,1772,383and427; Baird Trans. | 



Chicago Ac. Nat. Sc, I. ii. 271. (Hob. Interior regipns of> All races of one specie* . 

 Arctic America.) 



fl F. lahradora, Aud. B. Am., pi. 161,1831. (Hah. Littoral regions | 

 of Arctic America. J 



** F. mexicanus, " Licht, Mus. Berol," Schleg. Abh. G-eb. Zool. Vergl., 1841, p. 15 = F. polt/a- 

 grus, Cassin, B. Cal. and Tex.. 1853, 88 ; B. N. Am., 1858, 12. 



++ F. columbarius, Linn., Syst. Nat., 1760, 128 ; Hypotriorchis columbarius, Gray, List,, 1844, 

 55; Cass. R. N. Am., 1858, 9. 



XX Hypotriorchis richardsonii, nobis. Seepage 145. (Hob. Interior of Arctic Am. ; U.S. 

 between Rocky Mts. and Mississippi River.) 



M F. femoralis, Temm., PI. Col. 121, 1834, 343. Hypotriorchis femoralis, Gray Gen. B. 



if F. tparvtrius, Linn, Syst. Nat. p. 128, 17G6. Tinnunculus sparve.rius, Vieill. Ois. Am. Sept. 



flfl F. sparveroides, Vigors, Zool. Journ. III. 436, 1827. Tinnunculus sparveroides, Gray, Gen. 

 B. (Bab. Cuba.) 



(1) Tinnunculus leucophrys, nobis. See page"147. (Hab. Cuba and Hayti.) 



[Dec. 



