CONTENTS 31 



Order Falconiformbs: Diurnal birds of prey — Continued 

 Suborder Falcones: True birds of prey — Continued 



Family Accipitridae — Continued Page 



Subfamily Circinae: Harriers 498 



Genus Circus Lac6p6de 498 



Circus cyaneus hudsonius (Linnaeus) 500 



Genus Geranospiza Kaup 516 



Key to the North and Middle American forms of 



Geranospiza 517 



Geranospiza nigra nigra (DuBus) 518 



Geranospiza nigra balzarensis Sclater 521 



Geranospiza nigra livens Bangs and Penard 523 



Family Pandionidae: Ospreys 523 



Genus Pandion Savigny ._ 525 



Key to the American forms of Pandion 527 



Pandion haliaelus carolinensis (Gmelin) 527 



Pandion haliaetus ridgwayi Maynard 541 



Family Falconidae: True falcons, laughing falcons, pygmy falcons, 



forest falcons, and caracaras 543 



Key to the subfamilies of Falconidae 544 



Key to the North and Middle American genera and subgenera of 



Falconidae 545 



Subfamily Herpetotherinae: Laughing falcons 548 



Genus Herpetoiheres Vieillot 550 



Key to the races of Herpetoiheres cachinnans 551 



Herpeiotheres cachinnans chapmani Bangs and Penard.. 552 



Herpetoiheres cachinnans cachinnans (Linnaeus) 555 



Subfamily Micrasturinae: Forest falcons 558 



Genus Micrastur Gray 559 



Key to the species and subspecies of Micrastur 561 



Micrastur semitorquatus naso (Lesson) 567 



Micrastur mirandollei extimus Griscom and Greenway__ 572 



Micrastur ruficollis guerilla Cassin 574 



Micrastur ruficollis inter stes Bangs 577 



Subfamily Polyborinae: Caracaras 578 



Genus Daptrius Vieillot 580 



Key to the species and subspecies of Daptrivs 581 



Daptrius americanus guatemalensis (Swann) 582 



Daptrius americanus americanus (Boddaert) 585 



Genus Milvago Spix 588 



Key to the species and subspecies of Milvago 589 



Milvago chimachima cordatus Bangs and Penard 592 



Genus Polyborus Vieillot 595 



Key to the species and subspecies of Polyborus 597 



Polyborus cheriway audubonii Cassin 600 



Polyborus cheriway cheriway ( Jacquin) 607 



Polyborus cheriway pallidus Nelson 609 



Polyborus lutosus Ridgway 610 



Subfamily Falconinae: True falcons 612 



Genus Falco Linnaeus 614 



Key to the North and Middle American forms of Falco. . 617 



Subgenus Gennaia Kaup 621 



Falco mexicanus Schlegel 623 



