458 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



Winter plumage, lores, forehead, and crown grayish white ; a cres- 

 cent mark around back of head, extended forward to eyes blackish. 

 In breeding season bill yellow, usually tipped with black ; tarsus and 

 feet orange-yellow ; in winter, bill blackish ; legs and feet dull yellow. 



Measurements (from Ridgway, I.e., p. 522). — Males, wing 163- 

 178 (168.1), tail 70-93 (81.2), culmen 26-31 (28.8), tarsus 14-15.5 

 (14.5) mm. 



Females, wing 160-167 (162.9), tail 61-85.5 (72.9), culmen 25.5-30 

 (27.5), tarsus 14-16 (14.7) mm. 



Migrant from the north. Status uncertain. 



The only report for this species is a sight record by Eugene Eisen- 

 mann, who saw 3 at Coco Solo, Canal Zone, on August 28, 1958, in 

 company with larger terns. 



Two races may be concerned in this species should it be found 

 regularly in Panama, the subspecies antillarum, paler gray above, of 

 the eastern United States, and one darker gray, found in the western 

 Mississippi Valley. The latter has been recognized as a distinct sub- 

 species, 5". a. athalassos, but its separation from the subspecies hrowni 

 of California and southward is not certain. 



THALASSEUS MAXIMTJS MAXIMUS (Boddaert): Royal Tern; 

 Gaviotin Real 



Sterna maxima Boddaert, Table Planch. Enlum., 1783, pi. 58. (French Guiana.) 



Largest of the terns found regularly in Panama, larger than the 

 laughing gull ; with orange or yellow bill. 



Description. — Length, 460 to 530 mm. Feathers on back of head 

 elongated, pointed, forming a crest. Adult, in breeding dress with 

 crown and crest deep black ; otherwise as in nonbreeding plumage. 



Nonbreeding plumage, forehead, lores, and forepart of crown 

 white ; rest of crown and space around eye streaked with black ; crest 

 sooty black ; back and wings light gray ; tail pale gray centrally, 

 with lateral feathers darker ; primaries in fresh plumage silvery gray 

 on the surface of the outer web, black underneath, with the gray 

 disappearing with wear to leave the feathers dull black. 



Iris dark brown ; bill orange to yellowish orange ; tarsus and toes 

 black. 



Measurements (from Ridgway, I.e., p. 468). — Males, wing 360- 

 382 (371), tail 147.5-192 (171.9), exposed culmen 59-68 (64.1), 

 tarsus 29.5-34.5 (31.8) mm. 



Females, wing 357-393 (374) ; tail 130-196.5 (167.5), exposed cul- 

 men 57.5-67 (62.7), tarsus 30-34.5 (32.6) mm. 



Migrant from breeding grounds outside Panamanian waters. Com- 



