92 BIRDS OF BRITISH GUIANA. 



Breeding-season. Unknown in British Guiana. 



Isest. Unrecorded in British Guiana. 



Eggs. Undescribed from British Guiana. 



Range in British Guiana. Abary River [McConnell collection). 



Ej'tralimital Range. Venezuela, Margarita, Aruba and Bonaire 

 I.-lands (in South America), North America, West India Ishmds, 

 and casually in Africa. 



Habits. Unrecorded in British Guiana. 



57. Sterna superciliaris. 

 Least Terx. 



Sterna superciliaris Yieill. X. Diet. d'Hist. Xat. xxii. p. 126, 1819 

 (Parascuav) : Quelcli, Timehri (2) v. p. 106, 1891 (Georgetown); 

 Saunders," Cat. B. Brit. Mus. xxv. p. 124, 1896 (Kupuruni River); 

 Brabourne & Chubb, B. S. Amer. i. p. 34, no. 330, 1912. 



Adult male. Head, hind-neck, and loral streak black; back, wings, 

 and tail pale ash-grey; primary-coverts and three outer primaries 

 blacki.sh, inner webs of the latter white on the basal portion ; 

 base of forehead and entire mider surface pearly white. Bill 

 green at base, yellow at tip ; tarsi and toes olive-yellow. 



Total length 228 mm., culmen 3t), wing 188, tail 83, tarsus IG, 

 middle toe and claw 19. 



The descri})tion is taken from an example obtained on the 

 Abary River in September 1907. 



Ad id t female. Similar to the adult male. AVing 185. 



Breeding-season. Unknown in British Guiana. 



Kest. Unrecorded in British Guiana. 



Eggs. Undescribed from British Guiana. 



Range in British Ginana. Bartica, Abary River {McConnell 

 collection); Rupununi River [Whitely] ; Georgetown (Quelcli). 



Extralimital Range. Surinam, Venezuela, and Colombia to 

 Paraguav and Arcjentina. 



Habits. Unrecorded in British Guiana. 



Genu^ RHYNCHOPS Linn. 



lilnjnclwps Linne, Syst. Xat. 10th ed. i. p. 138, 1758. Type R. nigra 

 Linn. 



The chief character of this genus of Terns is the peculiar bill, 

 which is much compressed and very thin.^ the lower nrandible 

 being longer than the u]iper one. 



