STERNA CASPIA, CASPIAN TERN. 667 



J. Tail forked. Primaries with white stripe. 



1. Bill orange, stout, 2.25 to 2.75 long, 0.50 to 0.66 deep at 



base ; gouys ouly about 1 long ; wing, 14 to 15; tar.sus, 

 about 1.25, decidedly not longer than middle toe and 

 claw rcgiw. 



2. Bill orange, comparatively slender, about 2.50 long, less 



than 0.50 deep at base ; gouys, about 1.50 loug ; wing, 

 12 to 13 ; tarsus, about 1, decidedly longer than middle 



toe and claw galericulata. 



B. Smaller and less robust. Bill black, tipped with yellow. Tail deeply 



forked, with narrow outer feathers cantiaca. 



STEENA (THALASSECJS) CASPIA, Pall. 



Caspian Tern. 



Sterna caspia, Pall., Nov. Comm. Petrop. xiv, 1770, 582 ("Mns. Carls, fasc. iii, pi. 62"). — 

 Gm., Syst. Nat. i, 1788, 603.— Lath., Tnd. Orn. ii, 1790, 603.— Eetz., Fn. Suec. 

 1800, 164.— Tp:mm., Man. 1815, 476 ; ii, 1820, 733.— Nilss., Orn. Suec. ii, 1821, 

 155.— Beehm, Eur. Viig. 1823, 680.— Steph., Gen. Zool. xiii, 145.— Jen., Man. 

 1835, 264.— Keys. & Blas., Wirb. Eur. 1840, 97.— Naum., V. D. x, 1840, 18, pi. 



248.— Macgil., Man. ii, 1842, 230 ; Brit. B. v, .— Schl., Rev. Crit. Ois. Eur. 



1844, 128.- Degl., Orn. Eur. ii, 1849, 337.— Gray, Gen. of B. iii, 1849, 658 ; List 

 Br. B. 1863, 238.— Lawk., B. N. A. 1858, 859.— Tuenb., B. E. Pa. 1869, 47 (New 

 Jersey).— Radde, Reise, ii, 1863, 388 (Siberia).— Coues, Key, 1872, 319. 



Thalassetis caspius, Boie, Isis, 1822, 563.— Coues, Pr. Phila. Acad. 1862, 537.— Verr., Pr. 

 Ess. Inst, iii, 1862, 161 (Maine). — Coues, ihid. v, 1868, 308. — Lawr., Ann. Lye. 

 N. Y. viii, 1866, 299.— Elliot, B. N. A. pi. 56. 



Thalasscus caspius var. imperatoi-, Coues, Pr. Phila. Acad. 1862, 538 (in text). — Ridgw., 

 Ann. Lye. N. Y. x, 1874, 391 (Illinois). 



Hydroprofine caspia, Kaup, Sk. Ent. Eur. Thierw. 1829, 91. 



Helopus caspius. Wagl., Isis, 1832, 1224. 



Sijlochelidon. caspia, Brehm, V. D. 1831, 770.— Bp., List, 1838,62; Compt. Rend. 1856, 

 772.— Lawr., Ann. Lye. N. Y. v, 1850, 37.— Blas., J. f. O. 1866, 82. 



Sterna ischegrava, Lepech., Nov. Comm. Petrop. xiv, 1770, 500, pi. 13, f. 2. 



Sterna megurhijnchos, Meyek, Tasch. Deut. Vog ii, 457. 



Sterna strenna, Gould, 



Thalassites mclanotis, Sw. (Fide Blas.) 



Sjilochclidon haltldca et schillingii, Brehm, V. I). 769, 770. 



(?) Sijlochelidon cayanensis, Bp., Compt. Rend. 1856, 772 (gives regia also). 



Hah. — The Northern hemisphere. Arctic America, and south along the Atlantic 

 coast to New Jersey. 



Adult, breeding plumage. — (No. 17978. Mus. S. I., from Hudson's Bay.) Bill abotit the 

 length of the head, very much longer than tlie tarsus, exceedingly robust, mucli com- 

 pressed, deep at the base, its tip not very acute. The culmen is ))road and llattened at 

 the base, more compressed and narrow anteriorly ; very regularly deelinate convex 

 throughout its whole length. The commissure is curved frouj the angle of the mouth 

 to the tip, the amount of declination increasing toward the ti[). The outline of the 

 mandibular crura is slightly concave ; the gonys is about straight ; the symphyseal emi- 

 nence only tolerably well marked. Tiie nasal groove is short and wicle, and becomes 

 quite obsolete before it reaches the tomia. The nostrils are of the ordinary shape aud 

 size, or slightly wideued, placed at the anterior extremity of the iiasiil fossa. Several 

 stria- proceed out from them on the upper mandible, but the lower is (|uite smooth. The 

 submental sjjace is tolerably broad, bare of feathers for about half its length. The 

 outline of the feathers on the up))er mandible is as in Sterna generally, but those on the 

 side are rather broad and rounded. 



The jialate is anti-ro-posteriorly very concave, but transversely it is very flat and 

 little arched or vaulted. For three inches from the tip the roof of the mouth is (juite 

 smooth, with ouly slight indications of a median ridgi; ; but there is on each sidi^ a 

 deep groove, just along the edge, for the reception of I lie inferior mandible. The nasal 

 aperture lu-gins 2J inches from the tip, and is rather more than an inch long. The two 

 lateral ridges are short, beginning only slightly in advance ol the nasal ajiertuie; but 

 they are greatly elevated, very conspicuous, and their ridges so largely papillate as to 

 appear almost serratcnl. 



\VingN of ordinary length and shape for this subfamily. The ])riuiaries an; quite 

 broad at tin ir bases, but about two or three inches from theii- (i]is become rapidly nar- 

 rower, and taper to their sleuder rounded apices. The tirst surpasses the second by 



