196 BIRDS OF BRITISH Gl'IAXA. 



white margins to those of the soapuhirs, lower back, tail, greater 

 upper wing-coverts, and tips of secondaries ; lesser upper wing- 

 coverts pale bine ; outer webs of secondaries dark green, but no 

 speculum formed ; base of forehead, sides of crown, sides of 

 face, and fore-neck dull white with dark shaft-lines ; throat uni- 

 form buffy-white ; remainder of the under surface pale brown 

 margined and irregularly marked with white ; axillaries and 

 median under wing-coverts white, marginal coverts brown edged 

 with white, the greater series greyish like the quill-lining. 



Total length 335 mm., culmen 37, wing 173, tail 65, tarsus 28. 



The specimen from which the description is taken was procured 

 on the A!)ary River in Xovembor 1906. 



Breeding-season. Unknown in British Guiana. 



Kest. Unrecorded in British Guiana. 



E(jgs. Undescribed from British Guiana. 



Range in British Guiana. Abary River {McConneU collection) ; 

 Rupununi Savannas and (.otinga River (Brown). 



Extralimital Range. Colombia, Ecuador, Peru, "West India 

 Islands, Central and Xorth America. 



JIahits. Unrecorded in British Guiana. 



Genus NOMONYX Ridgw. 



Nomonyx Ridgway, Proc. U.S. Nat. Mus. iii. p. 15, 1880. Type 

 N. dojJiinicus (Linn.). 



This genus is dislingnished by having the nail of the bill 

 perpendicular, the tail longer than the tarsus, and the tail-feathers 

 narrow and stiff. 



124. Nomonyx dominicus. 

 AVhite-winged Lake Ulck. 



Anas (lominica Linn. Syst. Xat. 12th ed. i. p. 201, 17GG (" Habitat in 



America nieridionali "). 

 Nomonyx dominicus Salvad. Cat. B. Brit. Mus. xxvii. p. 438, 1895; 



Braboui-ne & Chubb, B. S. Amer. i. p. 58, no. 535, 1912. 



Adult male. Top of head, sides of face, and chin uniform black, 

 or aark brown like the lesser upper wing-coverts, quills, ami tail ; 

 remainder of the up|)er surface and sides of the body chestnut 

 with dark centres to the feathers, being more uniform chestnut on 

 the nape and throat ; wing speculum white ; under surface dull 



