42 FALCONID^. 



arrangement of the Falconidse (1875); but by incorporating some of Mr. Eidgway's 

 conclusions, this concordance is made closer. 



We have, following Dr. Coues, already removed Pandion from this family. We 

 nov? further modify our plan by using the curious character of the relative positions 

 of the distal ends of the coracoid, scapular, and clavicle, first indicated by Huxley and 

 subsequently brought into prominence by Mr. Kidgway, to separate Micrastur from the 

 Accipitrinse, and place it in a separate subfamily next Eerpetotheres, and near the 

 Falconinae and the Polyborinse. We also merge the Buteoninse in the Aquilinse, as 

 Dr. Coues has done. 



We thus have one group (A) consisting of four subfamilies, viz. Circinae, Accipitrinae, 

 Aquilinse, and Milvinae, in which the scapular process of the coracoid does not meet 

 the end of the clavicle, and another (B) also containing four subfamilies, viz. Herpeto- 

 therinse, Micrasturinse, Falconinae, and Polyborinae, in which the scapular process of 

 the coracoid meets the end of the clavicle. 



These eight subfamilies are represented in our region by thirty-three genera and about 

 sixty-four species, a very large proportion of the genera and species of the Falconidse 

 of the world. Of the genera eight are widely spread and extend beyond the limits of 

 America, seven are found in North as well as South America, and eighteen belong only 

 to Mexico and Central America and the southern continent. The Falconidae, therefore, 

 of our region, as regards their. genera, are much more nearly allied to those of South 

 America than they are to those of North America ; and as regards the species this 

 relationship is more clearly shown, a large proportion of them being identical in the 

 two regions. 



Group A. 



Subfam. CIRCINJE. 



This subfamily includes the Harriers {Circus) only, a compact group of birds with 

 marked characteristics, of which the most evident is the disc or ruff" which surrounds 

 the face, as in the Owls. The members of the genus Micrastur also have this feature 

 to a less extent, but they, again, are separated by the arrangement of the ends of the 

 coracoid, scapular, and clavicle mentioned above. 



CIECUS. 



Circus, Lacepede, Mem. de I'Inst. iii. p. 506 (1806) ; Sharpe, Cat. Birds Brit. Mus. i. p. 50. 



A genus of very wide distribution, containing about fifteen species. These are spread 

 over the temperate and tropical portions of all the larger land-areas of the world. In 

 North America Circus hudsonius is the only species, and this, as shown below, ranges in 

 winter as far south as the Isthmus of Panama. In South America two species occur 



The sexes in Circus hudsonius are very distinct in coloration, the male being a 



