COLYMBUS. 



Genus COLYMBUS Linn^us. (Page 4, pi. I., figs. 2, 3.) 



Species, 

 o}. Wing 5.00 inches or more. 



b^. Bill about as long as the head. Wing more than 6.00 inches. (Subgenus 

 Colymbus.') 

 c^. Feathers of lower parts pure white to the extreme base. Nuptial 

 plumage : Throat and chin buffy white, passing posteriorly into rich 

 ferruginous on the very prominent auricular frill, which is tipped 

 with black ; top of head and elongated tufts on each side of occiput 

 glossy black. • Length 22.00-24.00 ; wing 6.80-7.75 ; culmen 1.75- 

 2.30. Sab. jSTearly cosmopolitan, but no authentic record for any 

 portion of America. 



C. cristatus Linn. Crested Grebe.^ 

 c^ Feathers of lower parts white only superficially, the concealed portion 

 being distinctly grayish. Nuptial plumage : Top of head dull black, 

 somewhat glossy ; rest of head ash-gray, bordered above and poste- 

 riorly by whitish ; neck rufous. 

 dK Length about 17.50 ; wing 6.45-7.00 (6.63) ; culmen 1.50-1.55 (1.53). 

 Mab. Northern portions of eastern hemisphere. 



C. grisegena Bodd. Red-necked Grebe.* 

 d\ Length 18.00-20.50; wing 7.30-8.10 (7.65) ; culmen 1.65-2.40 (2.02). 

 Eggs 2-5, 2.23 X 1-37. Hab. North America, including Green- 

 land, breeding far northward ; eastern Asia. 



2. C. holboellii (Eeinh.). Holbcell's Grebe. 



b'^. Bill much shorter than head. Wing not more than 6.00 inches. (Subgenus 



Dyfes Kaup.) 



c'. Bill compressed (deeper than wide) at base. Nuptial plumage : Lower 



neck and chest rufous ; sides of occiput with a very full dense 



tuft of soft, blended, ochraceous feathers. Downy young : Whole 



top of head dusky; sides of head whitish with two stripes and 



several irregular spots of duskj^ ; a dusky streak on each side of 



throat ; upper parts plain dusky grayish. Length 12.50-15.25 ; wing 



about 5.75. Eggs 2-7, 1.78 X 1-20. Hab. Northern portion of 



northern hemisphere, breeding in America chiefly north of the 



United States 3. C. auritus Linn. Horned Grebe. 



&. Bill depressed (wider than deep) at base. Nuptial plumage : Head, neck, 

 and chest black ; sides of head, behind eyes, with a tuft-like or 

 somewhat fan-shaped loose patch of slender ochraceous feathers. 

 Downy young : Top of head dusky, with several white markings, the 

 middle of the crown with a small naked, reddish space ; no dusky 



1 Colymbus cristatus LiNN., S.N. ed. 10, 1758, II'.S. 



2 Colymhus grisegena BoDD., Tabl. P. E, 1783, 55. 



