SULA. 



75 



Genus SULA Brisson. (Page 74, pi. XIX., figs. 1, 2.) 



Nest a rude platform of sticks, etc., on rocks, trees, or bushes by sea-shore. 

 Eggs 1-2, elliptical or elongate-ovate, chalk-white superficially, but beneath the 

 calcareous crust pale greenish blue. 



Species. 



a 1 . Whole lower jaw, together with chin and entire throat, naked. (Subgenus 

 Sula.) 

 b 1 . Young with upper parts variegated. 



Young (?) : Head, neck, and lower parts white ; upper parts dark 

 grayish brown, the feathers with white tips; bill purplish, the 

 upper mandible grayish horn-color; feet dusky (in dried skins); 

 wing 14.60, tail 7.75, culmen 3.60, depth of bill at base 1.20. Sab. 

 Coast of Peru. 



S. variegata (Tschtjdi). Peruvian Booby. 1 

 b 2 . Young with upper parts unicolored. 



c 1 . Naked skin of face and throat blackish (dark bluish in life). 



Adult : White, theremiges, greater wing-coverts, primary coverts, 

 and alula dark sooty brown ; middle tail-feathers hoary whitish, 

 dusky at tips ; rest of tail-feathers dark sooty brown, whitish 

 basally ; feet reddish (drying pale brownish or yellowish). 

 Young : Head, neck, and upper parts plain dark grayish brown, 

 part of the back and rump streaked with white ; lower parts 

 white, the flanks streaked with grayish ; length 25.50-29.00, 

 wing 16.15-17.80, tail 7.75-9.10, culmen 3.95-4.15, depth of bill 

 at base 1.40-1.60. Eggs 2, 2.46 X 1-74. Bab. Intertropical 

 seas, especially the South Pacific and in West Indies, breeding 

 north to the Bahamas ; southern Florida. 



114. S. cyanops Sund. Sine-faced Booby. 



c 2 . Naked skin of face and throat light colored (yellowish or reddish in 



life). 



d 1 . Feet greenish or yellowish. Adult : Head, neck, breast, and upper 



parts dark sooty brown, the head and neck hoary grayish, in 



older (?) specimens, sometimes nearly white anteriorly ; lower 



parts, from breast backward, white. Young : Nearly uniform 



sooty brown, paler beneath. Length 30.00-31.00, wing 14.15- 



16.60 (15.72), tail 6.50-9.70 (8.23), culmen 3.25-3.95 (3.74), 



depth of bill at base .95-1.40 (1.24). Eggs 2, 2.24 X 1-58. Sab. 



Tropical and subtropical coasts of America, north to Georgia 



and northwestern Mexico 115. S. sula (Linn.). Booby. 



1 JDyiporus variegatus Tschudi, Weigm. Arohiv. 1843, 390. Sula variegata Scl. & Salt., Nom. Neotr. 

 1873, 124. 



