1000 SYSTEMATIC SYNOPSIS.— LONGIPENNES. 



colored. No hood nor collar. Most of head, back of neck, and upper parts in general, slaty- 

 gray, transversely waved with brownish-white, each feather being tipped with this color. Under 

 parts white. Tail white, with a terminal bar of black, 1.00 wide on middle feathers, growing 

 narrower on the others successively, on outermost sometimes invading only one web ; this black 

 bar very narrowly edged with white. Wings similar to those of adult, but white on inner webs 

 more restricted, and white tips very small or wanting altogether. Dimensions less than those 

 of adult; length about 13.00; wing 10.25, etc. Young not distantly resembling the same age 

 of Ch. Philadelphia. Arctic America, both coastwise and in the interior, irregularly S. in win- 

 ter through the U. S., as in New York, Utah, Colorado, Texas; Bermudas; Peru! Europe. 

 Common in high latitudes, but less so in the U. S., especially on the Atlantic side; breeding 

 range circumpolar. Eggs 3, 1.75 X 1-25, brownish-olive, sparsely splashed with brown, laid 

 iu June, July. Nestlings spotted with black above, pale gray below. 



CREAG'RUS. (Gr. Kpedypa, kreagra, a pot-hook, flesh-hook ; Kpeas, Jcreas, flesh, dypevco, 

 agreuo, I seize, catch, take.) Swallow-tailed Gulls. Tail deeply forked. Head hooded, 

 but neck not collared. Bill about as long as tarsus, stout at base, where deeper than at angle, 

 tip strongly hooked. Tarsus rather shorter than middle toe and claw. Size large, about equal- 

 ling that of a Herring Gull. One species. Neotropical. (Xema, in part, of former editions 

 of Key.) 



C. furca'ta. (Lat. fureata, forked.) Swallow-tailed Gull. Neboux's Gull. Adult 

 ^ 9) breeding plumage : Head and upper neck hooded with slate color, interrupted by a con- 

 spicuous white patch at base of bill. Mantle pearl-gray, interrupted with white outer edges of 

 scapulars ; outer six jDrimaries marked with black ; other primaries pale gray, edged with 

 white; most of the secondaries and coverts, tail, and under parts, white. Bill black, broadly 

 tipped with grayish-white ; gape and edges of eyelids orange-red; iris brown; feet red. Young: 

 No hood ; head white, with dusky spots about eyes and ears ; mantle and tail-feathers spotted 

 with black. Bill dusky ; feet pale, probably flesh-colored in life, drying brownish. This Gull 

 runs through the usual changes of plumage, but is unmistakable in any guise ; the most re- 

 markable feature is the white mark on the face, in the dark hood. Length of adults 20.00- 

 22.75; extent up to 52.50; wing about 16.50; tail 7.50, forked 3.00; bill along cubnen 2.00, 

 its depth at base 0.67, at angle 0.50; tarsus 2.00; middle toe and claw rather more. 9 av- 

 eraging smaller than ^, and young with wing under 16.00, tail less forked, etc. Originally 

 described from Monterey, California, perhaps in error; but see Auk, 1895, p. 291, for probable 

 occurrence at San Diego, Cal. This bird is native to the Galapagoes ; found also on the coast 

 of Peru, at Paracas Bay, and on Malpelo Island, off Bay of Panama. At date of 2d edition of 

 Key, 1884, only 3 specimtms were known, as then stated; in 1895 there were 9, as noted by 

 the A. 0. U. ; and 20 were catalogued soon afterward. Larus furcatus Neboux, Voy. Venus, 

 Atlas, 1846, pi. x. Xema furcatus Brvcu, 1853. X. furcatum Gray, 1871 ; Coues, Key, 

 1872, p. 317; Saunders, P. Z. S. 1878, p. 210, 1882, p. 523, pL xxxiv; X. furcata Coues, 

 1882; Key, 2d-4th eds. 1884-90, p. 753; Saunders, Cat. B. Brit. Mus. xxv, 1896, p. 165. 

 Creagrus furcatus Bp. 1854; A. 0. U. Hypothetical List, 2d ed. 1895, p. 326; Ridgw. Pr. 

 U. S. Nat. Mus. xix, for 1896, p. 638, with detailed descriptions and measurements of 20 

 specimens. 



Subfamily STERNIN/E: Terns, Sea-swallows. 



Covering of bill continuous (no cere), hard and horny throughout. Bill paragnathous, 

 relatively longer and slenderer than that of Gulls, very acute ; commissure straight or nearly 

 so to the very end; curve of culmeu gentle from base to tip. Symphysis of inferior mandibular 

 rami much more extensive than in Stercorariince or Larince, but eminentia symphysis less 

 marked. Interramal space narrow. Encroachment of feathers on bill as in Larince. Nostrils 

 linear-oblong, lateral, direct, pervious, varying with genera as regards nearness to base of bill. 



