1050 SYSTEMATIC SYNOPSIS. —PYGOPODES—GAVI^. 



pointed, dull greenish-drab, with dark brown and blackish spots. {Colymhus torquatus of most 

 authors, as of former editions of the Key; Urinator imber of A. 0. U. Lists, 1886-95.) 

 G. ad'amsi. (To Dr. C. B. Adams.) Yellow-billed Loon. Adams' Diver. Larger 

 than G. imber; bill rather larger, somewhat differently shaped and colored. Bill about 

 equalling head, longer than tarsus, much compressed, tip very acute, not at all decurved ; cul- 

 men and commissure almost perfectly straight ; gonys straight or nearly so to the prominent 

 angle. Frontal antise reaching beyond middle of nostrils. Bill light yellowish horn-color, 

 only dusky at base. Head and neck deep steel-blue, with purplish and violet reflections, 

 glossed only on cervix with green. Throat-patch of white streaks smaller than in imber, 

 but the individual streaks larger, as are those of the neck-patches. White spots of upper 

 parts larger than in imber, longer than broad instead of square on the scapulars. Length 

 35.00-38.00; wing averaging 15.00; culmen 3.50-3.75; gape 5.00-5.25; height of bill at 

 nostrils 0.95-LlO; width 0.40-0.50; tarsus 3.50, thus rather shorter than culmen; outer toe 

 4.65-5.10. Average dimensions thus somewhat exceeding those of imber; extension of loral 

 feathers and proportions of tarsi and toes the same. Arctic America, Hudson's Bay to Bering 

 Sea, common ; Siberia to Japan ; also occasional in Europe. Colymbus adamsi of former 

 editions of Key ; Urinator adamsii, A. 0. U. Lists, 1886-95.) 



G. arc'ticus, (Lat. arcticus, arctic.) Arctic Loon. Black-throated Diver. Adult 

 (J 9 ) ill summer : Bill black, shaped as in imber, but smaller ; feet blackish ; eyes red. Chin, 

 throat, and neck in front black, with purplish and violet reflections on sides of head, gradually 

 fading into clear bluish-gray of crown, nape, and hind neck, deepest on forehead, lightest be- 

 liind, separated from black of throat by a series of white streaks; a crescent of sliort, white 

 streaks across upper throat ; sides of breast and neck striped with pure white and glossy black, 

 these stripes nearly meeting in front. Upper parts glossy greenish-black, each feather of 

 scapulars and interscapulars with a white spot near end of each web, the scapular spots largest, 

 forming four patches in transverse rows ; wing-coverts thickly speckled with small ovate white 

 spots. Inner webs of quills, and tail-feathers below, light grayish-brown. Sides under wings 

 like back. Lining of wings and under parts from neck, pure white, with a narrow dusky band 

 across lower belly; under tail-coverts dusky, tipped with white. Young: Bill light bluish- 

 gray, dusky along ridge ; eyes brown ; feet dusky. Upper part of head and neck dark gray- 

 ish-brown ; sides of head grayish-white, ininutely streaked with brown. Upper parts with a 

 reticulated or scaly appearance, the feathers being brownish-black with broad bluish-gray 

 margins ; rump brownish-gray. Primaries and their coverts brownish-black ; secondaries and 

 tail-feathers dusky, margined with gray. Fore part of neck grayish-white, minutely and 

 faintly dotted with brown, its sides below streaked with the same. Lower parts, including 

 under surface of wings, pure white, the sides of body and rump, with part of lower tail-coverts, 

 dusky, edged with bluish-gray. Adults in winter resemble the young; they are distinguished 

 from the foregoing by smaller size, and from lumme by not being spotted on the back ; the 

 frontal antiaj are shorter than in imber and adamsi, hardly extending half way from base of 

 culinen to end of nostrils. Downy young sooty, paler below. Length 27.00-30.00; extent 

 40.00 or more ; wing 12.00-13.00 ; culmen 2.45 ; gape 3.40 ; height of bill at nostrils 0.65 ; 

 width there 0.35 ; tarsus 2.90 ; outer toe and claw 3.80. Northern part of Northern Hemi- 

 sphere ; common in Arctic America, where it breeds in June and July ; rare or casual in 

 winter in northerly portions of the U. S., chiefly E. of the Rocky Mts. Eggs indistinguishable 

 from those of the foregoing, but averaging smaller, about 3.10 X 2.00. 



G. pacif icus. (Lat. pacificus, pacific.) Pacific Loon. Lawrence's Black-throated 

 Diver. Like the last; colors the same, only paler gray on hind head and neck. Bill shorter, 

 slenderer, somewhat differently shaped, with straight culmen. Size small : Length about 24.00 ; 

 extent 40.00 or less ; wing 11.25-12.25, averaging under 12.00 ; culmen 1 .90-2.20 ; gape 3.00 ; 

 depth of bill at nostrils 0.50 or less; tarsus about 2.50. N. W. America, breeding only far 



