CASPIAN TERN. 667 



6. Tail forked. Primaries with white stripe. 



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



base ; gonys only about 1 long ; wing, 14 to 15 ; tarsus, 

 about 1.25, decidedly not longer than middle toe and 

 claw - regioe. 



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



than 0.50 deep at base ; gonys, about 1.50 long ; wing, 

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



toe and claw galericulata. 



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



forked, with narrow outer feathers cantiaca. 



STEENA (THALASSEdS) GASPIA, PaU. 



Caspian Tern. 



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

 Gm., Syst. Nat. i, 17S8, 603.— Lath., Ind. Orn. ii, 1790, 803.— Eetz., Fn. Snec. 

 1800, 164.— Temm., Man. 1815, 476 ; ii, 1820, 733.— NiLSS., Orn. Suec. ii, 1821, 

 155.— Beehm, Eur. Vog. 1823, 680.— Stbph., Gen. Zool. xiii, 145.— Jen., Man. 

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



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



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

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

 Jersey).— Eaddb, Eeise, ii, 1863, 388 (Siberia).— Coues, Key, 1872, 319. 



Thalasseus caspius, BoiB, Isis, 1822, 563.— Codes, Pr. Phila. Acad. 1862, 537.— Vekr., Pr. 

 Ess. Inst, iii, 1862, 161 (Maine).— CoUES, itid. v, 1868, 308.— Lav/k., Ann. Lye. 

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



Thalasseus caspius var. imperator, CouES, Pr. Phila. Acad. 1862, 538 (in text). — Eidgw., 

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



Hydroprogne caspia, Kattp, Sir. Ent. Eur. Thierw. 1829, 91. 



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



Sulochelidon caspia, Beehm, V. D. 1831, 770.— Bp., List, 1838,62; Compt. Rend. 1856^ 

 772.— Lawr., Ann. Lyo. N. Y. v, 1850, 37.— Blas., J. f. 0. 1866, 82. 



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



Sterna megarhynchos, Meybk, Tasch. Deut. Vog ii, 457. 



Sterna strenna, GoULD, 



Thalassites melanotis, Sw. (Fide Blas.) 



Sylochelidon halthica et schillingii, Brehm, V. 1). 769, 770. 



(?) Sylochelidon cayanensis, Bp., Compt. Eend. 1856, 772 (gives regia also). 



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

 coast to New Jersey. 



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

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

 pressed, deep at the base, its tip not very acute. The culmen is broad and flattened at 

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

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

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

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

 nence only tolerably well marked. The nasal groove is short and wide, and becomes 

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

 size, or slightly widened, placed at the anterior extremity of the nasal fossa. Several 

 striae proceed out from them on the upper mandible, but the lower is quite smooth. The 

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

 outline of the feathers on the upper mandible is as in Sterna generally, but those on the 

 side are rather broad and rounded. 



The palate is antero-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 quite 

 smooth, with only slight indications of a median ridge ; but there is on each side a 

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

 aperture begins 2f inches from the tip, and is rather more than an inch long. The two 

 lateral ridges are short, beginning only slightly in advance of the nasal aperture ; but 

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

 appear almost serrated. 



Wings of ordinary length and shape for this subfamily. The primaries are quite 

 broad at their bases, but about two or three inches from their Hps become r.apidly nar- 

 rower, and taper to their slender rounded apices. The first surpasses the second by 



