A History of 

 The Birds of Colorado 



KEY OF THE ORDERS. 



This Key is adapted from that in Ridg way's " Manual 

 of North American Birds," and must be used with caution 

 as it is impossible to construct a perfect key to the orders 

 of birds on external characters alone ; in cases of doubt, 

 reference should always be made to the diagnoses of the 

 orders themselves. 



A. Hind and front toes connected by a web. Steganopodes, p. 26. 



B. Hind toe, if present, never so connected. 



a. Cutting-edges of the bill rnore or less fringed or dentate ; 



toes completely webbed. Anseres, p. 30. 



b. Cutting-edges of the bill not fringed or dentate. 



a^ Legs inserted far behind the middle of the body, so that 



when standing the position is more or less erect ; toes 



webbed or lobed. Pygopodes, p. 3. 



b^ Legs inserted near the middle of the body, so that when 



standing the position is more or less horizontal. 



a^ Anterior toes very fully webbed and tarsus shorter than 



tail. Longipennes, p. 12. 



b" Anterior toes not, or not fully, webbed, 

 a^ Lower portion of the thighs naked. 



a* Hind toe long and inserted nearly at a level with 

 the others ; claws never excessively lengthened ; 

 loreal or orbital regions, or both, naked. 



Heriodiones, p. 73. 



B 



