OHYZOBOIIUS. 425 



(0. crassirostris), which, however, is much more common in and 

 around the city than the twa-twa." 



In habits this bird closely resembles the other Finches. 



617. Oryzoborus crassirostris. 



Thick-billed Seed-Finch. 



Loxia crassirostris Gmel. Syst. Nat. i. p. 862, 1789 (Guiana). 



Ooccohorus ater Cab. in Schomb. Eeis. Guian. iii. p. 678, 1848. 



Oryzoborus crassirostris Salvin, Ibis, 1885, p. 214 (Bartica Grove) ; 

 Sharpe, Cat. B. Brit. Mus. xii. p. 79, 1888 (Bartica Grove, George- 

 town) ; Beebe, Our Search for a Wilderness, p. 142, 1910 (Hoorie 

 Creek) ; Brabourne & Chubb, B. S. Amer. i. p. 363, no. 3722, 1912. 



Oryzoborus crassirostris crassirostris Beebe, Tropical Wild Life in 

 British. Guiana, p. 136, 1917 (Bartica)i 



"Thick^billed Pygmy Grosbeak" (Beebe); " Twa-twa " (Quelch). 



Adult male. General colour, both on the upper and under sur- 

 face, black; base of flight-quills white, which extends to the outer 

 web on some of the outer primaries, and forms a white speculum ; 

 axillaries, under wing-coverts, and basal portion of quills below 

 white, the under wing-coverts more or less marked with black ; 

 apical portion of quills below pale brown ; lower aspect of tail 

 dark brown. 



Total Ifength 145 mm., exposed culmen 13, wing 69, tail 57, 

 tarsus 20. 



The exact locality in British Guiana, of the specimen from 

 which the description is taken, is unknown. 



Adult female. Differs from the adult male in being olive-grey 

 on the upper parts, fawn-colour on the under surface, and in the 

 absence of the wing-speculum. Wing 68 mm. 



The immature male, in its first plumage, is similar to the adult 

 female. 



The descriptions of the adult female and young male are 

 taken from examples in the British Museum, collected by 

 the late Henry Whitely at Annai, July 1889, Salvin-Godman 

 collection. 



Breeding-season. November (Schomhurgk) . 



JS'est. Built of mosses lined with plant-wool, and placed in 

 thickly foliaged bushes (Schomhurgk). 



Eggs. Undescribed from British Guiana. 



