COLTMBUS AECTICUS, BLACK-THEOATED DIYEE. 721 



c.uliiion convex; commissure somewhat decnrved; gouys convex, with slight angle. 

 Frontal antia- falling short of middle of nostrils. Gloss of head and neck mostly j,'reen. 

 White spots of back nearly square. 



I'ar. ADAMSii : Culmen, aboat 3.75 ; gape, about 5 ; height of bill at nostrils, aver- 

 age, over 1. Bill along culmen longer than tarsus. Color of bill mostly yellow ; its 

 culmen nearly straight; commissure straight; gonys straight, with prominent angle. 

 Frontal anti* reaching middle of nostrils. Gloss of head and neck mostly blue. ^Yhite 

 spots of back longer than broad. 



The type of this form was from Enssian America, now Alaska. Numer- 

 ous specimens in l-reeding i^lumage have been received at the Smith- 

 souian from various parts of Arctic America. The form appears to have 

 been also recorded in Asia, and is even quoted from England. I have 

 seen uo United States examples ; nor have I recognized the bird in its 

 young' i)htmage, wheu. ijrobably, it coidd not be distinguished with any 

 certainty from ordinary torquatus. Specimens are labeled as having 

 the iris light reddish-brown, the feet olivaceous. 



yotwithstandiug the distinctions in the size, shape, and color of the 

 bill, I am now rating this bird as- a variety of torquatus, being satis- 

 fied that the characters iutergrade with those of the latter. 



COLTMBUS AECTICUS, Linn. 

 ^ Black-throated Direr. 



a. arctieux. 



Colijmhus arctiats. Lixx.. Svst. Xat. i, 1766, •J-::!!.— Cm.. Svst. Xat. 1, ITSS. .=i?7.— Lath., 

 Ind. Orn. ii, 17^0. >tO.— Brlxx., Orn. Bor. 17G4. \o. 133.— TEini., Man. Om. 

 1;1.5. 599.— Steph.. Gen. Zool. xii, 1S24. 236.— Keys. & Bias., "SVirb. Eur. 1S40, 

 91.— Gkat, Gen. of B. iii, 631, pi. 171.— Sl-xd., Svcnsk. Fiigl. pi. 53.— Bp.. .Syn. 

 1^2~, 4C0; Lisr. 1?:!^, 65 — Arc., Orn. Biog. iv, 163:^. 345. pi. 346: Svn. l-!39, 

 3,")4 ; B. Am. vii, 1~44. iQj, pi. 477.— Xutt., Man. ii, 1^34, 517.— Sw". i Rich., F. 

 B. A. ii, l;ol. 475.— Lawk., B. X. A. 1-5::. c55 ; Ann. Lvc. X. Y. viii, 1866, 3C0 

 (Xew York).— Corrs. Pr. Phlla. Acad. 1S62, ii?.- Cour j. Pr. Ess. Inst. v. 1S6^. 

 309 iXew England).— Daix A: Baxx., Tr. Chic. Acad. 1.-59, 307 (Alasku).- 

 F:xsCH, Abh. Nat. iii, 1>7-', 74 (^Uaska).— Cotxs. Key, 1-72, 334.— Cori:~, Elli- 

 otts Pryhilov Islands, 1>74. — Etdgw., Ann. Lye. X. Y. x, 1^74, 392 (Illinois) ; 

 and of authors generally. 



Ceppltm artik-tts. Pall., Zoog. U'-A. ii, IS 11, 91. 



Eudijtes arciiciis. Ill,, Prod. 1611, 282.— Xaum., V. D. xii, 1544, 418, pi. 328. 



Coli/mbus macrorhi/tichos, Brehji, Y. D. 1831. 974. 



Colifmhus megarhynehos. Bi;ehm, Xaum. v, 1855, :W0 ; V. D. 974. 



C'llymlius baWtkus, Hop.x.?ch., Verz. Pommersch. Vog. 21. 



" Coli/mbus ignolus et leucopus, Becust., Xaturg. iv, 7^2." 



b. pacijicus. 



CvJiDiilus pacifiais, Lawr., B. X. A. 18.3-, 889.— CouES. Pr. Phila. Acad. 1862. 228.— Coop, 

 & Suck., X. H. Wash. Ter. 1860. 279.— Coces. Ibis, 1666, 273 (Southern Cali- 

 fornia). — CouES, Pr. PhOa. Acad. Is66, luO. 



Colymbus arciicus var. padficus, CciUES, Key, 1872, 335. 



Sab. — The JTorthem hemisphere. Yar. pacijicua from the Pacific coast of Xorth 

 America. 



This species, which was not noticed by either of the Expeditions, appears to be a 

 more northerly bird than the last, and, according to my experience, it is rare in the 

 United States, Audubon, however, states that it comes as far south as Texas. The 

 Pacific variety is a common bird on the coast of California in winter. 



Tar. AECTicrs : Black-tliroated Diver. 



Ch^vt.. BUI generally as in torquatus, but smaller ; color black. Chin, throat, and 

 neck in front, black, with purplish and violet reflections oil the sides of the head, grad- 

 ually fading into a fine, clear bluish-gray, deejiest on the forehead, ligbest behind, and 

 separated from the black of the throat by a series of white streaks. A crescent of short, 

 white streaks across upper throat ; sides of breast striped with pure white and glcssv 

 46 



