278 [February, 



in Lieut. Whipple's collection is smaller. Its dimensions are as follows : Total 

 length 16 inches, wing 12i, tail 7 inches. The young male of this species is in 

 Dr. Henry's collection, and differs from the adult only in being somewhat darker 

 in color, though not so dark as the young female described by me as above. 



3. Htpotriorchjs femoralis, (Temm.) 



A fine specimen and the first ever noticed within the limits of the United 

 States, is in the collection made by Dr. A. L. Heermann, who was attached to 

 the surveying parties in charge of Lieuts. Williamson and Parke, U. S. A. It 

 is an adult in fine plumage, and precisely identical with the South American bird. 

 Jt was obtained in New Mexico.* 



4. Tinnunculus sparverius, (Linn.) 



Numerous specimens from various localities demonstrate that this species 

 inhabits the whole of western (as well as eastern) North America. Specimens 

 from Tamaulipas, Mexico, are in Lieut. Couch's collection ; from San Francisco, 

 California, in Lieut. Trowbridge's; from Utah Tenitory, in Lieut. Beckwith's ; 

 and from Milk River, a tributary of the Upper Missouri, in the collection of Dr. 

 George Suckley, attached to the party in charge of the Hon. 1. I. Stevens. 



5. Hierofalco candicans, (Gmelin.) 



Falco candicans, Gm. Syst. Nat. i. p. 275, (1788.) 



Falco groenlandicus, Daudin, Tr. d'Orn, ii. p. 107, (1800.) 



Falco fuscus, Fabricius, Fauna Groenlandica, p. 56, (1780.)? 



"Falco arcticus, Holboll." Label on specimens received from Europe. 



Adult. ^ White, under parts with a few longitudinal narrow stripes of brown. 

 Upper parts white, head and neck behind with longitudinal narrow stripes of 

 brown. Plumage of the back, wing coverts and shorter quills with irregular 

 confluent transverse bands, and large snbterminal hastate or bluntly sagittate spots 

 of ashy brown* Primary quills white with their tips brownish black, and with 

 irregular and imperfect transverse bars of black, confluent on the shafts of the 

 feathers. Tail white, with transverse bars of brownish black in some of the 

 outer feathers, only observable on their outer webs. 



Dimensions. Total length (of skin,) about 24 inches, wing 16, tail 10 inches. 



Young. Entire upper plumage with the brown predominating, and of a lighter 

 shade than in the adult, and tinged with ashy; every feather edged with white, 

 and more or less barred and spotted with white, and pale reddish. The brown 

 color showing a tendency to form the bands and sagittate spots of the adult. 

 Under parts white, tinged with ashy, with longitudinal stripes of brown, widest 

 on the abdomen. Quills ashy brown, with transverse bands of white tinged with 

 pale fulvous, tail ashy brown, palest on the middle feathers, every feather edged 

 externally with white, and with imperfect transverse bands (or pairs of large 

 spots, ) of white. 



This fine species is nearly related to that next described, but can be distin- 

 guished by the different style of the brown marking of the upper parts. In the 

 present bird, the large subterminal sagittate or hastate spots are especially cha- 

 racteristic, and this character prevails also in the young bird. 



The nomenclature of this and the succeeding species is difficult to determine 

 on account of their similarity. 



6. Hierofalco islandtcus, (Gmelin.) 



Falco islandicus, Gm. Syst. Nat. i. p. 275, (1788.) 

 Falco islandus, Fabricius Faun. Groenl., p. 58, (1780) ? 



* In Lieut. Couch's collection there are specimens of the following species 

 from Mexico. 



1. Hypotriorchis columbarius, (Linn.) from the State of Tamaulipas. 



2. Hypotriorchis rufigularis, (Daudin.) from the State of New Leon. This 

 species has not yet been detected within the limits of the United States ; but as 

 1he State of New Leon is only separated from Texas by the Rio Grande, it will 

 very probably be found in the State last mentioned. 



