252 BIRDS OF ILLINOIS. 



FAMILY URINATORnXffi. THE LOONS. 



CHAEACTEBS. Swimming birds, with the feet situated far back, a well developed hal- 

 lux. and anterior toes completely webbed and normally clawed; the bill straight, acute, 

 compressed, the nostrils linear, overhung by a membranous lobe; tail normal, but short. 

 Nature prtecocial. Nest on ground at edge of marsh or lake ; eggs two, elongate-ovate, 

 deep brown or olive, rather sparsely speckled or spotted with dark brown and blackish. 



GENUS UBINATOR CUVIER. 



Colymbus LINN. 8. N. ed. 10, i. 1758, 135; ed. 12, i, 1766, 220 (part). 



Mergus BEISS. Orn. vi, 1760, 104 (not of LINN. 1758). 



Uria SCOP. Introd. 1777. 473 (not of BBISS. 1760). 



Urinator Cuv. Anat. Comp. i, 1799, tabl. ii. Type, Colymbus imber GUNK. 



Eudytes LLIJG. Prodr. 1811, 282 (same type). 



GEN. CHAB. The same as those of the Family, as given above, in addition to 

 which are the following characters of coloration: Above blackish or slaty, beneath white. 

 Adult: Upper parts spotted or speckled with white, the throat and fore-neck blackish 

 or chestnut. Young: Upper parts without white markings, and throat and fore-neck 

 white like rest of lower parts. Downy young: Uniform sooty grayish, the belly while. 



The known species are all North American, and may be dis- 

 tinguished by the following characters: 



A, Tarsus shorter than middle toe without claw; fore- neck blackish in summer. 



a. Distance from base of culmen to anterior point of loral feathers, above nostrils, 

 greater than the distance from the latter point to anterior border of nostrils. 

 Summer plumage with head and neck black all round, the middle of the fore-neck 

 and sides of lower neck each crossed by a bar, or transverse series, of white 

 streaks. 



1. U. imber. Tarsus longer than exposed culmen; bill in adult blackish (almost 

 wholly deep black in summer); head and neck glossed with velvety green; white 

 spots on scapulars broad as long; length 28.00-36.00; wing tt.00-15.2i (14.06); culmen 

 2.75-8.50 (3. 07); depth of bill through base .90-1.05 (.96). 



[2. TT. adamsii (Yellow-billed Loon). Tarsus shorter than exposed culmen; bill in 

 adult whitish (almost wholly yellowish white in summer); head and neck glossed 

 with velvety violet-blue; white spots on scapulars decidedly longer than broad; 

 length about 35. 00-38. 00; wing 14.85-15. 45 (15.11); cu'.men 3.50-3.65 (3.59); depth of 

 bill through base 1.00-1.20 (1 .09). Hob. Western Arctic America and northeast- 

 ern Asia.] 



&. Distance from base of cuhnen to anterior point of loral feathers, not greater than 

 distance from the latter point to anterior extremity of nostril. Summer plumage 



