TABLE OF CONTENTS. XV 



Page. 



Genus 1. Cryptoglaux Richmond 622 



Key to the Species and Subspecies of Cryptoglaux 623 



1. Cryptoglaux tengmalmi richardsoni (Bonaparte) 624 



2. Cryptoglaux acadica (Gmelin) 627 



3. Cryptoglaux ridgwayi Alfaro 633 



Genus 2. Scotiaptex Swainson 634 



Key to the Subspecies of Scotiaptex nebulosa 635 



4. Scotiaptex nebulosa nebulosa (Forster) 635 



Genua 3. Strix Linna?us 639 



Key to the Species and Subspecies of Strix 641 



5. Strix varia varia (Barton) 641 



6. Strix varia alleni (Ridgway) 644 



7. Strix varia albogilva Bangs 646 



8. Strix varia sartorii (Ridgway) 646 



9. Strix fulvescens (Sclater and Salvin) 647 



10. Strix occidentalis occidentalis (Xantus) 648 



11. Strix occidentalis caurina (Merriam) 650 



12. Strix occidentalis huachucse (Swarth) 651 



13. Strix occidentalis lucida (Nelson) 652 



Genus 4. Asio Brisson .' 652 



Key to the Species of Asio 654 



14. Asio wilsonianus (Lesson) 654 



15. Asio etygius (Wagler) 658 



16. Asio flammeus (Pontoppidan) 661 



17. Asio portoricensis Ridgway 667 



18. Asio galapagoensis (Gould) 668 



Genus 5. RhinoptynLX Kaup 670 



19. Rhinoptynx clamator (Vieillot) 671 



Genus 6. Pseudoscops Kaup 674 



20. Pseudoscops grammicus (Gosse) 674 



Genus 7. Gymnasio Bonaparte 676 



Key to the Species and Subspecies of Gymnasio 676 



21. Gymnasio nudipes nudipes (Daudin) 677 



22. Gymnasio nudipes newtoni (Lawrence) 679 



23. Gymnasio lawrencii (Sclater and Salvin) 679 



Genus 8. Otus Pennant 681 



Key to the Species and Subspecies of Otus 684 



24. Otus asio asio (Linnaeus) 687 



25. Otus asio nagvius (Gmelin) 690 



26. Otus asio mccallii (Cassin) 693 



27. Otus asio hasbroucki Ridgway (New subspecies) 694 



28. Otus asio aikeni (Brewster) 695 



29. Otus asio maxwellise (Ridgway) 696 



30. Otus asio macfarlanei (Brewster) 697 



31. Otus asio kennicottii (Elliot) 698 



32. Otus asio brewsteri Ridgway (New subspecies) 700 



33. Otus asio bendirei (Brewster) 701 



34. Otus asio cineraceus (Ridgway) 702 



35. Otus asio xantusi (Brewster) 703 



36. Otus trichopsis (Wagler) 704 



37. Otus pinosus (Nelson and Palmer) 708 



38. Otus vinaceus (Brewster) 708 



39. Otua cooperi (Ridgway) 710 



