I'HAETHrsA. 87 



G-enns PHAETHUSA Wagler. 

 Fhaefusa Wagler, Isis, 1S32, p. 1224. Type P. chloropoda (Vieill.). 



This monotypic genus of Terns is characterized by its large bill, 

 vhich is twice the length of the tarsus, and the rounded or slightly 

 ])ointed taii-feathers^ the tail being less than half: the length o£ 

 the wino-. 



53. Phaethusa cMoropoda. 



Great-billed Tern. 



Phaefhusa cliloropoda (Vieill.), X. Diet. d'Hist. Xat. xxxii. p. 171, 



1S19 (Pai-aguav) ; Braboui-ne & Chubb, B. S. Amer. i. p. 33, 



no. 319, 1912. ' 

 Sterna magnirostris Licht., Cab. in Schomh. Eeis. Guian. iii. p. 761 



(1848; ; Salvin, Ibis, 1886, p. 180; Quelch, Timehri (2) v. p. 106, 



1S91 (Georgetown). 

 Phaefhusa magnirostris Saunders, Cat. B. Brit. ^us. xxv. p. 23, 1896 



(River Eupunini, Ourumee) ; Beebe, Our Search for a Wilderness, 



p. 154, Waini, p. 378, Abary, 1910. 



Adult male. Crown of head black ; entire back, scapulars, and 

 inner lesser upper wing-coverts grey, as also the tail ; a narrow 

 line at the base of the forehead, fore part of face, and entire 

 nnder surface, including the axillaries and under wing-coverts, 

 white with a shade of grey on the sides of the body; the small 

 coverts round the bend of the wing, median, and greater upper 

 wing-coverts also white, some of the greater series tinged with 

 grey ; bastard-wing feathers grey on the outer web, blackish on 

 the inner one; primary-coverts and quills black with some white 

 on the inner webs of the latter; secondaries grey, inner webs white; 

 tertials for the most part grey with whitish ti[ts. '* Bill chrome- 

 yellow, slightly greenish at the base of the lower mandible ; feet 

 olive, webs yellow." 



Total length 363 mm., exposed portion of cuimen 02, wing 300, 

 tail 113, tarsus 24. 



The bird described was collected on the Abary River. 



Adult female. Similar to the adult male. ^Ving 30r> mm. 



Young birds differ from the adults in having the head giey and 

 the tail-feathers fringed with white at the tijis. 



BreediiHi-season. Unknown in British Guiana. 



Kest. Unrecorded in British Guiana. 



E<i[ts. Undescribed from British Guiana. 



liaiKjc in B/dhlt (Juiana. Ituribisi liiver, Supenaam Kivor, 



